Overview

The year 843 was a year of major political and religious change in medieval Europe. It is best known for the Treaty of Verdun, which partitioned the Carolingian realm, and for the formal restoration of the veneration of icons in the Byzantine Empire. These developments had long-lasting effects on the map and institutions of Europe.

Major events

  • Treaty of Verdun: In August 843 the three surviving sons of Louis the Pious reached an agreement that divided the Carolingian Empire into three kingdoms. The partition created distinct western and eastern polities and a middle territory that would influence the later borders of modern France, Germany and parts of Italy.
  • Byzantine restoration of icons: After decades of conflict over religious images, imperial and ecclesiastical authorities in Constantinople re-established the use and protection of icons, an action celebrated in eastern Christianity as the Triumph of Orthodoxy.
  • Regional activity: Norse raids and settlements continued to reshape parts of the British Isles, Ireland and the Frankish coasts, while smaller polities across Iberia and Italy adjusted to shifting power among local rulers and external pressures.

Culture and religion

The settlement in Byzantium marked a decisive end to the period known as Iconoclasm and restored the production and public display of religious images, influencing worship, liturgy and sacred art for centuries. In western Europe, the division of Carolingian authority accelerated local political fragmentation and encouraged distinct court cultures to develop.

Legacy and significance

The agreements and decisions taken in 843 contributed directly to the political outline of medieval western Europe. The Treaty of Verdun is often regarded as a turning point that set the stage for the emergence of separate kingdoms that would evolve into modern nation-states. The religious settlement in Constantinople shaped Orthodox Christian practice and identity. Scholars studying medieval law, diplomacy, and church history frequently point to 843 as a pivotal year.

Calendar and dating

In contemporary chronologies 843 is recorded as a common year beginning on Monday in the Julian calendar. For calendar context and how medieval years are reckoned, see Julian calendar resources and summaries of early medieval chronology here.