The Battle of Manzikert or Malazgirt was fought between the Byzantine Empire and the Seljuk Empire on 26 August 1071 near Manzikert, theme of Iberia. The decisive defeat of the Byzantine army and the capture of the Emperor Romanos IV Diogenes played an important role in undermining Byzantine authority in Anatolia and Armenia, and allowed for the gradual Turkification of Anatolia. Many Turks, travelling westward during the 11th century, saw the victory at Manzikert as an entrance to Asia Minor.

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.