The Kingdom of the Lombards, also known as the Lombard Kingdom and later as the Kingdom of all Italy, was an early medieval state established by the Lombards, a Germanic people, on the Italian Peninsula in the latter part of the 6th century. The king was traditionally elected by the very highest-ranking aristocrats, the dukes, as several attempts to establish a hereditary dynasty failed. The kingdom was subdivided into a varying number of duchies, ruled by semi-autonomous dukes, which were in turn subdivided into gastaldates at the municipal level. The capital of the kingdom and the center of its political life was Pavia in the modern northern Italian region of Lombardy.

The Byzantine Empire, also referred to as the Eastern Roman Empire, was the continuation of the Roman Empire centered in Constantinople during Late Antiquity and the Middle Ages. The eastern half of the Empire survived the conditions that caused the fall of the West in the 5th century AD, and continued to exist until the fall of Constantinople to the Ottoman Empire in 1453. During most of its existence, the empire remained the most powerful economic, cultural, and military force in the Mediterranean world. The term "Byzantine Empire" was only coined following the empire's demise; its citizens referred to the polity as the "Roman Empire" and to themselves as "Romans". Due to the imperial seat's move from Rome to Byzantium, the adoption of state Christianity, and the predominance of Greek instead of Latin, modern historians continue to make a distinction between the earlier Roman Empire and the later Byzantine Empire.