The Importance of the Libri Carolini: Parts 1-4

Introduction: The Libri Carolini and the Rejection of Nicaea II

The veneration of religious images remains one of the most divisive theological issues in Christian history. In 787 AD, the Second Council of Nicaea (Nicaea II) declared that icons were to be given douleia (veneration), distinguishing this from latreia (worship). This decision was met with strong resistance from the Frankish Church, which, under Charlemagne’s direction, produced the Libri Carolini—a comprehensive refutation of Byzantine iconodulism. This Frankish theological treatise argued that any form of religious reverence toward images, no matter how nuanced, inevitably leads to idolatry and corrupts true Christian worship. Rooted in Scripture and the early Church tradition, the Libri Carolini upheld a Christ-centered approach to worship that rejected both the Byzantine embrace of images and the extreme iconoclasm of certain Eastern emperors.

The significance of the Libri Carolini extends far beyond the Carolingian era. Its rejection of Nicaea II was formalized at the Council of Frankfurt (794 AD), which condemned the Byzantine council’s decrees and asserted the theological independence of the Frankish Church. This moment foreshadowed later disputes over the authority of Rome and the role of tradition in Christian doctrine. Indeed, many of the arguments advanced in the Libri Carolini found new life during the Protestant Reformation, where Reformers such as Martin Luther, John Calvin, and Ulrich Zwingli similarly rejected the veneration of images in favor of a worship grounded in the Word and Sacraments.

This essay, once consisting of 4 separate essays, will explore the theological and historical foundations of the Libri Carolini, demonstrating its biblical rejection of image veneration and its assertion of Iconopraxism—a position that allowed for the use of religious images for education while prohibiting any form of reverence toward them. By engaging with Scripture, the Church Fathers, and the theological traditions of both the early Church and the Reformation, this study will argue that the Council of Frankfurt, not Nicaea II, represents the true biblical stance on Christian worship. Furthermore, it will highlight the enduring significance of the Libri Carolini in shaping the trajectory of Western Christianity, particularly in its insistence that Christian worship must be directed toward God alone, free from the distractions of human innovations that lead to idolatry.

Part 1: The Rejection of Image Veneration 

The Libri Carolini was written as a theological response to the decrees of the Second Council of Nicaea (787 AD), which sought to restore the veneration (douleia) of images in the Christian Church. However, the Frankish court, under Charlemagne’s direction, strongly opposed the Byzantine ruling, arguing that it contradicted Scripture and the true tradition of the early Church. The Libri Carolini, structured into four books, systematically refuted the iconodule position, asserting that image veneration led inevitably to idolatry and corrupted Christian worship.

Books 1 and 2 of the Libri Carolini lay the groundwork for this argument by:

Critiquing the theological justification for icon veneration presented at Nicaea II.

Demonstrating the biblical prohibition of image devotion.

Appealing to early Church authorities who opposed religious images.

Warning against the corruption of true Christian worship through materialistic and external practices.

This first section of our analysis will explore these themes, highlighting the Frankish insistence on a biblical, Christ-centered worship devoid of human innovations like image veneration.

The Purpose of the Libri Carolini and Its Context

The Libri Carolini arose in a specific theological and political climate that shaped its arguments.

The Byzantine Council of Nicaea II and Its Errors

Nicaea II, convened in 787 AD under Empress Irene, sought to restore the veneration of icons, which had been suppressed by Byzantine iconoclast emperors (e.g., Leo III, Constantine V). The Byzantine bishops declared that icons should receive douleia (veneration), distinguishing this from latreia (worship). However, the Frankish theologians rejected this distinction as an artificial justification for idolatry.

The Libri Carolini argues that any form of religious reverence given to images, no matter how slight, inevitably leads to worship, a practice forbidden in Scripture.

The Faulty Latin Translation of Nicaea II

The Frankish court received an inaccurate Latin translation of Nicaea II’s decrees, which made it seem as though the Byzantines required the worship (latreia) of images rather than simply veneration (douleia). This misinterpretation, though relatively minor, contributed to the Libri Carolini’s strong response. However, even apart from this translation error, the Frankish theologians maintained that any reverence toward images—even mere veneration—was doctrinally corrupt.

The Influence of Charlemagne and the Frankish Theologians

Charlemagne, who saw himself as a new Constantine, sought to define the theological boundaries of Western Christianity apart from Byzantine influence. The authorship of the Libri Carolini is often attributed to Theodulf of Orléans, one of Charlemagne’s leading theologians. The work expresses a distinctly Frankish theological vision, rooted in biblical authority and Augustinian tradition.

Thus, the Libri Carolini was not only a doctrinal response but also a political statement of Western theological independence from the Byzantine East.

Biblical and Theological Arguments Against Iconodulism

The Libri Carolini’s first major argument is that the veneration of images is explicitly condemned in Scripture and contrary to the essence of Christian worship.

The Artificial Distinction Between Latreia and Douleia

The Frankish theologians reject the Byzantine claim that icons receive only douleia (veneration) rather than latreia (worship). The treatise argues that in practical reality, all forms of religious reverence given to images amount to idolatry.

The Libri Carolini states:

“No created thing, whether in heaven or on earth, deserves to receive honor as though it were divine.” (Libri Carolini, Book 3, Chapter 17)

The Biblical Condemnation of Idolatry

The Frankish theologians root their rejection of icons in Scripture, citing:

• Exodus 20:4-5 – "You shall not make for yourself a carved image… You shall not bow down to them or serve them."
• Deuteronomy 4:15-16 – "You saw no form on the day that the Lord spoke to you at Horeb… lest you act corruptly by making a carved image."
• Romans 1:25 – "They exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator."

The Libri Carolini insists that images of Christ, Mary, or the saints inherently violate these commands, as they misdirect religious devotion from the invisible God to material objects.

The Golden Calf as an Example of Misguided Worship

The treatise highlights the story of the Golden Calf (Exodus 32):

• The Israelites did not intend to worship a false god; rather, they said: "Tomorrow shall be a feast to the Lord" (Exodus 32:5).
• Even though their worship was directed to Yahweh, their use of an image was condemned as idolatry.
• The Libri Carolini argues that the same principle applies to Christian images—even if people claim they are “venerating” Christ through an icon, it remains a violation of true worship.

The Church Fathers and Early Christian Opposition to Icons

The Libri Carolini reinforces its argument by appealing to early Church Fathers who opposed the veneration of images.

• Epiphanius of Salamis (4th Century) – "I found a painted image of Christ or one of the saints in a church. I tore it down and ordered it to be destroyed." (Panarion 27:6)
• Augustine of Hippo (5th Century) – "For images are more likely to mislead an unhappy soul, since they have a mouth and speak not, eyes and see not." (De Vera Religione, 55)
• Gregory the Great (6th Century) – "Images are made for instruction, not for adoration." (Epistle to Serenus of Marseilles, Book IX, Letter 105)

These quotes demonstrate that early Christian tradition did not endorse icon veneration, but instead cautioned against its dangers.

Iconopraxism: The Frankish Alternative to Iconoclasm and Iconodulism

At this point, the Libri Carolini introduces a theological middle ground:

• Against Iconodulism – Rejects veneration of images as unbiblical.
• Against Iconoclasm – Rejects destruction of images, allowing them for education.

This permissive but non-venerative approach can be described as Iconopraxism—the use of religious images without attributing any religious devotion to them.

The Libri Carolini states:

"Images are useful in churches not because they are to be venerated, but so that they may instruct the ignorant." (Libri Carolini, Book 2, Chapter 27)

Thus, the Frankish Church established a biblical, Christ-centered model for worship that neither worshiped nor rejected images entirely.

Part 2: The Use of Images in Christian Worship

While Book 1 of the Libri Carolini focused on refuting the veneration of icons, Book 2 begins transitioning from this rejection into defining the proper role of religious art, a discussion that continues into Book 3. These books establish that images can serve a didactic function but must never be venerated, and they emphasize that Christ’s true presence in worship is found in the Word and Sacraments, not in icons.

These sections of the Libri Carolini also establish a firm theological foundation for how Christ is truly present in worship, emphasizing that his presence is found in the Word and the Sacraments, not in physical images. This distinction sets the Frankish view apart from both Byzantine iconodulism and iconoclasm, while reinforcing the biblical and early Christian tradition of worship that focuses on spiritual engagement with God rather than external forms.

Thus, Books 2 and 3 clarify:

1. The proper use of religious images for education, not for veneration.
2. The true presence of Christ in Christian worship, which is found in the Word and Sacraments, not in icons.
3. The failure of the iconodules to distinguish between external forms and spiritual reality, which leads to the materialization of Christian devotion.

This section will explore these arguments in detail, demonstrating that the Frankish position provides the most biblically faithful and theologically sound approach to images and worship.

The Proper Use of Images: Education, Not Devotion

The Libri Carolini makes it clear that religious images are not inherently sinful, but their function in the Church must be limited to teaching. The Frankish theologians explicitly reject the iconoclastic position, which sought to destroy all religious images, and instead affirm their value in instructing the faithful. However, they draw a sharp distinction between educational use and religious devotion.

The treatise states:

"Images are useful in churches not because they are to be venerated, but so that they may instruct the ignorant." (Libri Carolini, Book 2, Chapter 27)

This aligns with Pope Gregory the Great, who wrote:

"Images are made for instruction, not for adoration." (Epistle to Serenus of Marseilles, Book IX, Letter 105)

These statements confirm that the Frankish position was consistent with earlier Western Christian thought, emphasizing that images could be used as aids to learning but should never be objects of religious reverence.

This argument is rooted in the nature of true Christian worship, which is not about external representations but about faith, understanding, and the inner reality of Christ’s presence.

Theological Critique of Iconodulism: The Corruption of Worship

While the Libri Carolini acknowledges that images can serve as visual teaching aids, it also warns that their misuse corrupts Christian worship by shifting attention from spiritual reality to material objects.

One of the strongest arguments in Books 2 and 3 is that Nicaea II failed to preserve the proper focus of Christian devotion, leading to a superstition-laden piety that prioritized external forms over genuine faith. The Frankish theologians feared that the excessive veneration of icons could obscure the spiritual nature of Christianity.

This concern is reflected in their critique:

"It is ridiculous to assert that the nature of wood and paint can become sacred." (Libri Carolini, Book 2, Chapter 27)

"No created thing, whether in heaven or on earth, deserves to receive honor as though it were divine." (Libri Carolini, Book 3, Chapter 17)

These passages underscore the Frankish rejection of materialistic devotion, maintaining that only God himself is to be honored, not any material object, even if it is religious in nature.

This argument is consistent with biblical teaching, particularly passages that emphasize the spiritual nature of Christian worship:

• John 4:24 – "God is spirit, and those who worship Him must worship in spirit and truth."
• Acts 17:29 – "Being then God's offspring, we ought not to think that the divine being is like gold or silver or stone, an image formed by the art and imagination of man."

Thus, the Libri Carolini reinforces the biblical rejection of material-centered worship, arguing that icons, while not inherently sinful, are a distraction from true devotion to God.

Christ’s Presence in Worship: The Word and Sacrament, Not Icons

Another critical argument in Books 2 and 3 is that Christ’s true presence in Christian worship is found in the Word and Sacrament, not in physical images. The Frankish theologians explicitly deny that icons can serve as legitimate mediators of Christ’s presence, rejecting the Byzantine iconodule belief that icons are “windows to the divine.”

The Libri Carolini argues:

"Christ did not give us images to venerate, but His very body and blood in the sacrament." (Libri Carolini, Book 4, Chapter 14)

This statement directly opposes the Byzantine claim that icons are a means of encountering Christ, asserting instead that Christ has given the Church a direct means of communion with him through the Eucharist and the preaching of the Word.

This position is entirely consistent with biblical teaching on Christ’s presence in worship:

• Matthew 26:26-28 – "This is my body… this is my blood of the covenant."
• John 6:53-56 – "Whoever feeds on my flesh and drinks my blood abides in me, and I in him."
• Romans 10:17 – "Faith comes from hearing, and hearing through the word of Christ."

The Frankish view maintains that Christ is present in worship, not through painted images, but through his real, ordained means of grace—the preaching of the Word and the celebration of the Sacraments.

This is a crucial point because it demonstrates that iconodulism misplaces the focus of Christian worship, shifting attention away from Christ’s true presence and onto man-made representations.

The Frankish critique highlights a fundamental theological principle:

• Christian worship is not about external representations but about encountering Christ through his ordained means.
• The use of religious imagery, if elevated beyond its didactic role, risks replacing true devotion with external ritual.

This argument would later resonate in the Protestant Reformation, where Reformers like John Calvin and Ulrich Zwingli similarly rejected the idea that Christ could be mediated through images, emphasizing instead the sufficiency of Word and Sacrament.

Part 3: The Political and Theological Significance of Book 4

The final book of the Libri Carolini shifts from theological arguments about icon veneration to a broader critique of Byzantine ecclesiastical authority and theological overreach. Book 4 is particularly important because it lays the groundwork for Frankish theological independence, challenging the idea that Rome or Byzantium had the right to impose doctrine on the entire Church without broader consensus.

The rejection of Nicaea II was not merely a theological stance—it was also a declaration that the Frankish Church had the right to determine its own doctrinal boundaries, distinct from Byzantine influence. This assertion would have profound consequences for the future of Western Christianity, foreshadowing the later schism between the Latin West and Greek East and even the debates leading to the Protestant Reformation.

Book 4 of the Libri Carolini makes three major arguments:

1. The Council of Nicaea II lacked true ecumenical authority, as it was dominated by the Eastern Church under Byzantine imperial control.
2. The Pope should not have accepted Nicaea II, as its decisions were theologically unsound and contradictory to biblical and patristic teaching.
3. The Frankish Church had the right to reject erroneous teachings, asserting theological autonomy from both Byzantium and Rome.

These arguments demonstrate that the Libri Carolini was not only a critique of iconodulism but also a statement of theological and political independence, asserting the right of the Western Church to reject doctrinal errors coming from the East.

The Council of Frankfurt (794 AD) and the Rejection of Nicaea II

One of the most significant outcomes of the Libri Carolini was its influence on the Council of Frankfurt (794 AD), convened by Charlemagne. This council gathered over 300 bishops from across the Frankish Empire and formally condemned the decrees of Nicaea II, reaffirming the Frankish rejection of icon veneration.

The Council of Frankfurt declared that Nicaea II was an error of the Greeks, stating:

"The synod of the Greeks which was held at Nicaea is neither accepted nor followed by us, but is entirely rejected." (Royal Frankish Annals, 794 AD)

Unlike Nicaea II, which was a council dominated by Byzantine politics, Frankfurt represented a more balanced gathering of Western bishops, free from imperial pressure. This reinforces the idea that Frankfurt, not Nicaea II, represents the true theological stance of the universal Church on images.

Theological and Political Critique of Byzantine Overreach

The Libri Carolini makes a strong case that Nicaea II should not be regarded as binding on the universal Church for two key reasons:

1. It was not truly ecumenical, as it was dominated by Byzantine bishops and imperial influence.
2. Its conclusions were theologically erroneous, as demonstrated in Books 1–3.

Byzantine theological councils often operated under imperial oversight, with the emperor playing a major role in enforcing doctrine. The Libri Carolini argues that this practice corrupted true Christian teaching, allowing imperial politics to shape theology.

The Frankish theologians rejected this model, arguing that Church doctrine should be based solely on Scripture and apostolic tradition, not on imperial decrees. The Libri Carolini states:

"The doctrine of the apostles was handed down to us not by imperial decrees, but by divine revelation." (Book 4, Chapter 6)

This is a direct challenge to the Byzantine approach to theology, which often involved imperial enforcement of conciliar decisions. The Franks insisted that true doctrine must be based on Scripture, not the will of emperors or politically motivated councils.

The Council of Frankfurt’s Rejection of Nicaea II and the Roman Church’s Departure from Biblical Christianity

Despite the authoritative rejection of Nicaea II by the Council of Frankfurt (794), the Roman Church ultimately conformed to Byzantine theology rather than upholding the Scriptural and patristic clarity of the Frankish critique. This shift was not a sudden theological breakthrough but the result of centuries of political entanglement, unchecked papal ambition, and a departure from biblical authority.

The Papacy’s Political Alignment with Nicaea II

A unique feature of the Libri Carolini is its criticism of the Pope’s acceptance of Nicaea II. Pope Hadrian I had initially supported the council, but the Frankish theologians argued that this support was misguided. They insisted that the Pope was fallible in this matter and that his acceptance of Nicaea II did not make it binding on all Christians.

This was a remarkable stance, as it implied that the Frankish Church had the right to evaluate and reject papal decisions when they contradicted biblical truth. While unfortunately the Franks still recognized the primacy of the Bishop of Rome, they denied that Rome’s decisions were infallible when they departed from true, biblical doctrine.

This foreshadowed later Western challenges to papal authority, including the Protestant Reformation, where Reformers like Martin Luther and John Calvin argued that Rome had erred in doctrinal matters and could be resisted on the basis of Scripture.

The Libri Carolini establishes this principle clearly:

"We do not reject the authority of Rome, but neither do we accept teachings that contradict the Scriptures, even if they come from the Pope himself." (Book 4, Chapter 12)

Even though Pope Hadrian I’s endorsement of Nicaea II was met with justified resistance from the Franks, subsequent popes reaffirmed the council’s decrees—not due to theological necessity, but largely because of political expediency. The Libri Carolini (Book 3, Chapter 17) explicitly denounces Hadrian’s support for Nicaea II, arguing that his theological reasoning was weak and his stance was influenced by his political alignment with Byzantium.

The Frankish Church’s Theological Legacy: A Forerunner of the Reformation

The Libri Carolini and the Council of Frankfurt represent an alternative and far more biblical trajectory for Western Christianity—one that, had it prevailed, would have spared the Church from centuries of error. The Frankish theologians correctly asserted that true doctrine must be determined by Scripture and the early Church Fathers, not by the unchecked decrees of popes or politically driven councils. In doing so, they prefigured the central conviction of the Protestant Reformation: that Church authority is not above God’s Word and that popes and councils can and do err.

This conviction was famously articulated by Martin Luther at the Diet of Worms (1521):

"Unless I am convinced by Scripture and plain reason—I do not accept the authority of popes and councils, for they have contradicted each other—I am bound by the Scriptures I have quoted and my conscience is captive to the Word of God. I cannot and will not recant anything, for to go against conscience is neither right nor safe." (Luther at Worms, April 18, 1521, recorded in the Acta Wormatiensia)

Luther’s words echo the principles already upheld by Charlemagne’s theologians centuries earlier. The Council of Frankfurt had already demonstrated that councils could err, that Scripture must be the final authority, and that theological independence from Rome was not only possible but necessary—something that true Christians have been trying to do all throughout church history.

Part 4: Legacy and Enduring Significance of the Libri Carolini

The Libri Carolini is one of the most significant theological treatises in early medieval history. While its primary goal was to refute the decrees of Nicaea II (787) and defend the Council of Frankfurt (794), its influence extended far beyond its immediate historical context. The theological vision it articulated—rejecting both iconodulism and iconoclasm while affirming a Word-centered worship—became an enduring force in shaping Western Christianity.

Despite the fact that the Catholic Church eventually sided with Nicaea II, the Libri Carolini played a crucial role in the theological trajectory of the West. It foreshadowed many later developments, including the medieval critique of excessive religious imagery, the Protestant Reformation’s return to biblical worship, and the modern debates over the role of images in Christian devotion.

This final section will explore the long-term impact of the Libri Carolini, focusing on:

1. Its influence on the medieval theological tradition and the evolution of Western Christianity’s approach to images.
2. Its connections to the Protestant Reformation, particularly in the Reformers’ rejection of religious images in worship.
3. Its relevance to modern debates about biblical worship, iconography, and the role of images in Christian devotion today.

The Libri Carolini and Medieval Theology

While the Council of Frankfurt rejected Nicaea II’s decrees, the Libri Carolini did not gain universal acceptance in later medieval theology. However, its arguments shaped ongoing debates about the use of religious images in the Latin West.

1. Early Medieval Influence (9th–11th centuries) – Although later popes reaffirmed Nicaea II, many in the West remained skeptical of the excessive veneration of images. The teachings of the Libri Carolini continued to influence the Carolingian Renaissance, where Word-based worship was prioritized over visual representations.
2. The High Middle Ages and the Scholastic Tradition (12th–13th centuries) – The scholastic theologians of this period, including Thomas Aquinas, provided a more structured defense of icon veneration (Summa Theologica III, q. 25, a. 3). However, even among Catholic theologians, there was debate about the proper limits of religious imagery.
3. Gothic Art and the Use of Religious Imagery – By the late medieval period, Catholic churches became increasingly reliant on visual representations, but there were still moments of anti-icon excess movements, such as the Cluniac reforms, which sought to refocus worship on Scripture and prayer rather than images.

Thus, while Nicaea II eventually shaped official Catholic doctrine, the Libri Carolini left a lasting imprint on the Western skepticism toward icons, ensuring that icon veneration in the West never reached the level of Byzantine iconodulism.

The Libri Carolini and the Protestant Reformation

The arguments laid out in the Libri Carolini foreshadowed many of the key theological battles of the Reformation, particularly the Reformers’ rejection of icons, statues, and visual devotion.

1. Martin Luther’s Position – Luther maintained that religious images were not inherently sinful, but he opposed their superstitious use in Catholic worship (Against the Heavenly Prophets, 1525). This was very similar to the Frankish approach in the Libri Carolini, which allowed images for teaching but forbade their veneration.
2. John Calvin and Ulrich Zwingli’s Iconoclastic Reforms – Calvin and Zwingli completely rejected the use of images in Christian worship, returning to the biblical focus on spiritual worship over external forms. Calvin’s position in Institutes of the Christian Religion (Book 1, Chapter 11) closely mirrors the arguments in the Libri Carolini, particularly in its rejection of both iconodulism and iconoclasm.
3. The Destruction of Religious Imagery in Protestant Regions – The Reformation led to widespread iconoclasm in many Protestant territories, particularly in Switzerland, Scotland, and parts of Germany. Churches were stripped of their statues, stained glass, and paintings, reflecting the Frankish insistence on Word-based worship rather than image-based devotion.
4. The Council of Trent (1545–1563) and the Catholic Response – The Catholic Church, reacting to the Protestant rejection of images, formally upheld Nicaea II’s icon veneration doctrine at the Council of Trent, further solidifying the divide between Word-based Protestant worship and image-based Catholic devotion (Canons and Decrees of the Council of Trent, Session 25).

The parallels between the Libri Carolini and the Reformation critique of idolatry demonstrate that the Frankish theologians were ahead of their time, offering a theological alternative that would later find greater acceptance among the Reformers than in medieval Catholicism.

The Libri Carolini and Modern Christian Worship

Even today, the core arguments of the Libri Carolini remain relevant in debates about Christian worship and the role of religious imagery.

1. The Evangelical, Liturgical Protestant, and Reformed Traditions – Evangelical Protestants and Reformed churches continue to reject the veneration of icons, adhering to the biblical principle that worship must be spiritual and Word-centered. Many churches today have minimal religious imagery, reflecting the Frankish and Reformation emphasis on preaching, prayer, and sacraments as the center of worship.
2. The Eastern Orthodox and Catholic Traditions – In contrast, Eastern Orthodoxy still holds to the rulings of Nicaea II, treating icons as an essential part of Christian devotion. The Catholic Church, while allowing for a broader range of worship expressions, also continues to endorse religious images as objects of veneration. The divide between Word-based worship and image-based devotion, which emerged in the Libri Carolini, remains a central theological difference between Protestant and Catholic/Orthodox traditions today.
3. The Debate Over Idolatry and Visual Media in Worship – Some modern Christian denominations struggle with how much visual representation should be allowed in worship. The rise of contemporary media, including videos, digital images, and artistic projections in worship services, raises similar concerns to those addressed in the Libri Carolini—whether external representations distract from true worship.
4. A Return to Biblical Worship – The Libri Carolini serves as a reminder that biblical worship is centered on the Word of God, not external images. Many churches today that emphasize expository preaching, prayer, and communion over visual elements are, in essence, following the theological vision set forth by the Frankish theologians.

Conclusion: The Libri Carolini and the Enduring Call for Biblical Worship

The Libri Carolini stands as one of the most important theological works of the early medieval period, articulating a vision of Christian worship that rejected both the idolatry of Byzantine iconodulism and the excessive destruction of iconoclasm. As the theological response of the Frankish court to the decrees of Nicaea II, it provided a biblically grounded, historically consistent, and theologically robust defense of Word-centered worship, setting a precedent that would resonate throughout church history.

Despite its rejection by the Roman Church in favor of Byzantine doctrine, the Libri Carolini remains significant for several reasons. It demonstrated the theological independence of the Frankish Church, laying the foundation for future Western challenges to the unchecked authority of popes and councils. It provided a biblical refutation of image veneration, showing that Christian worship must be directed toward God alone, rather than mediated through material representations. It also anticipated the arguments of the Protestant Reformation, which would later reaffirm the sufficiency of Scripture over ecclesiastical traditions that departed from biblical truth.

The Council of Frankfurt’s rejection of Nicaea II should have been the standard for Christian worship, preserving the purity of biblical faith against human innovations. However, the gradual political and theological alignment of the papacy with Byzantine tradition led the Catholic Church to embrace the veneration of images, despite the clear biblical and patristic opposition presented in the Libri Carolini. This decision ultimately contributed to the deepening corruption of medieval worship and widened the divide between true biblical Christianity and the traditions of Rome.

Yet, the Libri Carolini did not fade into irrelevance. Its insistence on biblical authority over human tradition, its rejection of material-centered piety, and its emphasis on the centrality of Word and Sacrament in worship continued to echo through the centuries. Its influence can be seen in the Reformation’s return to biblical worship, the continued skepticism toward excessive religious imagery in the West, and the modern Evangelical emphasis on preaching and spiritual worship rather than external forms.

The theological principles championed in the Libri Carolini remain vital for the Church today. As contemporary Christianity wrestles with issues of idolatry, visual media in worship, and the proper balance between tradition and Scripture, the insights of the Frankish theologians provide a clear and urgent call: Christian worship must be founded on Scripture alone, centered on Christ, and free from the distractions of human inventions that lead away from true devotion.

As history has shown, the errors of Nicaea II led the Church further from biblical faithfulness. But the Libri Carolini stands as a testimony that there were those who sought to defend the purity of Christian worship against corruption. Its voice still calls out today, urging believers to hold fast to the Word of God as the sole rule of faith, rejecting all forms of idolatry, and worshiping God in spirit and truth.