The Revival of the Western Roman Empire

By the late 8th century, the fragmented legacy of the Western Roman Empire is challenged by the rise of the Franks under Charlemagne. Building upon the foundations laid by his father, Pepin the Short, and grandfather, Charles Martel, Charlemagne embarks on an ambitious campaign of conquest, unifying much of Western and Central Europe under his rule. His expansion is not merely military but also ideological, as he promotes Christianity as a unifying force across his empire.

In 800, in a moment of profound historical symbolism, Pope Leo III crowns Charlemagne Emperor of the Western Roman Empire, reviving a title that had been vacant for more than three centuries. This act cements the alliance between the Frankish monarchy and the papacy, laying the foundation for what would later be known as the Holy Roman Empire—a political entity that would shape European history for centuries to come.

East Central Europe (676–819 CE): Collapse of the Avar Khaganate, Rise of Slavic Principalities, and Carolingian Expansion

Between 676 and 819 CE, East Central Europe—including present-day Poland, Czechia, Slovakia, Hungary, and regions of Germany and Austria east of 10°E and north of an imaginary line from roughly 48.2°N at 10°E southeastward to the Austro-Slovenian border near 46.7°N, 15.4°E—experienced transformative political, cultural, and social changes. This period was defined by the decline and eventual collapse of the powerful Avar Khaganate, the rapid emergence and strengthening of Slavic principalities, and significant eastward expansion by the Carolingian Empire, culminating in Charlemagne’s conquest of the Avars. The result was a dramatically altered regional landscape that laid the foundation for the later medieval kingdoms of Central Europe.

Political and Military Developments

Decline and Fall of the Avar Khaganate

• From the late 7th century, the once-dominant Avar Khaganate entered prolonged decline due to internal conflicts, external pressures from Slavic groups, and incursions from neighboring powers.

• In 796 CE, Charlemagne, king of the Franks, decisively defeated the Avars along the Danube. The Franks captured extensive treasures, including vast amounts of gold and silver, which substantially financed the subsequent Carolingian Renaissance.

Rise and Expansion of Slavic Principalities

• During this era, numerous Slavic principalities emerged, notably in Moravia and Bohemia, laying the foundations for later states such as Great Moravia and the Duchy of Bohemia.

• In modern-day Poland, tribal federations began coalescing into structured territorial entities, marking the first steps toward future Polish statehood.

Carolingian Empire and Eastern Frontier

• Carolingian campaigns brought Frankish control into regions of modern Austria, western Hungary, Bavaria, and Thuringia, significantly reshaping political boundaries.

• Charlemagne established border territories known as Marches (notably the March of Pannonia), intensifying Frankish influence over regional political, economic, and military structures.

Economic and Technological Developments

Economic Revival and Trade Networks

• The collapse of the Avars revitalized regional economic activity by redirecting trade networks westward, facilitating exchanges between Slavic territories and Carolingian lands.

• Enhanced economic stability promoted agricultural productivity, metalworking, and increased commerce, benefiting greatly from Carolingian coinage and trade integration.

Carolingian Agricultural and Technological Influence

• Advanced agricultural techniques, improved ironworking technologies, and superior fortification methods introduced by the Carolingian Empire significantly shaped economic practices and technological development across the region.

Cultural and Artistic Developments

Contributions to the Carolingian Renaissance

• Captured Avar treasure substantially funded cultural, artistic, and educational initiatives central to the Carolingian Renaissance, including monasteries, churches, and scholarly centers.

Slavic Cultural Consolidation

• Slavic principalities developed distinct cultural identities, visible archaeologically through unique pottery styles, jewelry, metalwork, fortified settlements, and evolving religious practices.

Settlement and Urban Development

Formation of Early Medieval Towns

• Early medieval urban centers and fortified hilltop settlements proliferated across Moravia, Bohemia, and adjacent regions, becoming essential hubs of political, economic, and cultural activity.

• Previously Roman and Avar fortifications were reconstructed and expanded under Frankish and Slavic influence, signaling sustained urbanization in medieval East Central Europe.

Social and Religious Developments

Christianization and Religious Integration

• Carolingian expansion accelerated the spread of Christianity throughout East Central Europe. Missionary activities grew significantly, laying critical foundations for future religious organization and cultural integration.

• Local populations adopted Christianity, blending new beliefs with existing indigenous practices, resulting in complex syncretic traditions.

Social Hierarchies and Feudal Precursors

• Social structures evolved toward hierarchical governance, influenced by emerging warrior elites, territorial rulers, and early forms of feudal relationships and vassalage. This laid the foundation for medieval governance patterns.

Integration and Assimilation of Avar Survivors

• Following their defeat, surviving Avars gradually assimilated into neighboring populations, primarily Slavic and later Magyar communities, preserving elements of their culture through metalwork, equestrian traditions, and technological influences.

Long-Term Consequences and Historical Significance

The period 676–819 CE was pivotal in shaping the historical trajectory of East Central Europe. The destruction of the Avar Khaganate and the appropriation of its treasures significantly contributed to the cultural and intellectual vigor of the Carolingian Renaissance, influencing broader European civilization. The formation and strengthening of early Slavic states created enduring ethnic, cultural, and political identities, laying groundwork for later medieval kingdoms. Finally, Carolingian expansion introduced new administrative frameworks, technologies, and religious structures, profoundly influencing the medieval development of the region for centuries to come.

A more stable polity emerges in Moravia more than a century after the demise of Samo's empire when the Czech tribes of Moravia help Charlemagne destroy the Avar Empire (ca. 796) and are rewarded by receiving part of it as a fief.

The Moravians pay tribute to Charlemagne, but they do enjoy considerable independence.

The Papacy’s Shift from Byzantium to the Franks

Between 756 and 857, the papacy gradually transitions from the influence of the East Roman Empire to the authority of the Frankish kings, a shift that reshapes the political and religious landscape of Western Europe. This transformation begins when the Lombards seize the Exarchate of Ravenna from the Byzantines, weakening the empire’s hold over Italy and leaving the papacy increasingly vulnerable.

Seeking protection, the popes turn to the rising power of the Carolingians. Pepin the Short, in alliance with the papacy, defeats the Lombards and grants the Papal States to the pope—a move that cements the Carolingians as the papacy’s chief defenders. This alliance deepens under Charlemagne and his son Louis the Pious, both of whom wield significant influence over the selection and administration of popes, ensuring that the church remains aligned with their imperial ambitions.

However, this close relationship weakens following the division of the Frankish Empire into West Francia, Middle Francia, and East Francia in 843. With no single dominant Frankish ruler, papal independence grows, marking the end of Carolingian control over the Holy See and setting the stage for future conflicts between church and state in medieval Europe.

The Franks, campaigning in areas of present Austria and Slovenia, meet with little resistance due to drought and famine in lands controlled by the Avars, Bulgars and Slavs, but ninety percent of Charles's horses, which in 791 carry their riders as far as Gyõr, on the Moson arm of the Danube, perish of famine.

Charles, King of the Franks, having made the Bavarian ducal residence of Ratisbon (Regensburg) his base, conducts several campaigns, partly under his own command, against the Avar kingdom (in modern Hungary and Upper Austria), who have dominated the middle basin of the Danube River throughout most of the seventh and eighth centuries.

From 791, the Franks war against the Avars, who control the central Danube River valley and have over the past centuries acquired a vast hoard of gold and silver plundered or extorted largely from Constantinople's holdings.

Avar co-rulers Kaghan and Yugrush die in 792 at the hands of their own men, who blame them for the drought and famine.

Subsequently, Avar leaders vie for control, and internal dissent troubles the Avar state.

The Frankish forces have from 791 warred against the Avars, who control the central Danube valley.

Charles, unsuccessful in tracking down and crushing the enemy after four years of campaigning, returns to his base at Regensburg to strengthen his forces on the eastern frontier.

Avar hegemony in the northern Balkans ends as the Franks, under Charles the Great, or Charlemagne, crush their empire and cart the Avar treasury west to Aachen, using the vast hoard of gold—protection money extorted for centuries from the Eastern Empire—to fuel the Carolingian Renaissance.