Digenes Akritas is a medieval Greek romantic epic that emerged in the 12th-century Byzantine Empire. It is the lengthiest and most famous of the acritic songs; Byzantine folk poems celebrating the lives and exploits of the Akritai, the inhabitants and frontier guards of the empire's eastern Anatolian provinces. The acritic songs represented the remnants of an ancient epic cycle in Byzantium and, due to their long oral transmission throughout the empire, the identification of precise references to historical events may be only conjectural. Set during the Arab-Byzantine wars, the poem reflects the interactions, along with the military and cultural conflicts of the two polities. The epic consists of between 3,000 to 4,000 lines and it has been pieced together following the discovery of several manuscripts. An extensive narrative text, it is often thought of as the only surviving Byzantine work truly qualifying as epic poetry. Written in a form of vernacular Greek, it is regarded as one of its earliest examples, as well as the starting point of Modern Greek literature.

Medieval Greek is the stage of the Greek language between the end of classical antiquity in the 5th–6th centuries and the end of the Middle Ages, conventionally dated to the Ottoman conquest of Constantinople in 1453.