What Byzantine empire is responsible for reconquering Roman empires?

Answer 1

There was only one empire which has been called Byzantine Empire by historians, who use this term to indicate the eastern part of the Roman Empire after the fall of the western part of this empire and which outlasted the latter by nearly 1,000 years. The people in question did not know this term and called their empire Roman Empire. It covered the eastern basin of the Mediterranean and part of the Balkan Peninsula in south-eastern Europe.

The emperor Justinian the Great set out to reconquer lands lost by the western part of the Roman Empire. He succeeded in reconquering Tunisia, western Libya and eastern Algeria (in 534), southern Spain (in 552) and Italy (in 554). However, these gains were eventually lost. Northern Italy and part of central Italy were lost 18 years after the 19-year war to retake it from the Goths (the Gothic Wars (535-554). They were invaded by the Lombards in 568. The Visigoths started retaking the lands they lost to the Byzantines in southern Spain 29 years after the Byzantine conquest of the area and this completed 70 years after the conquest. North-western Africa was conquered by the Arabs between 665 and 700. In 751 the Lombards attacked the other territories in central Italy and the Byzantine fled. In 753 the Franks took over the area and gave to the pope. The Byzantines became restricted to southern Italy.