Early Medieval Europe

Eastern Roman Empire

Justinian's successors Maurice and Heraclius confronted invasions by the Avar and Slavic tribes. After the devastations by the Slavs and the Avars, large areas of the Balkans became depopulated. In 626 Constantinople, by far the largest city of early medieval Europe, withstood a combined siege by Avars and Persians. Within several decades, Heraclius completed a holy war against the Persians, taking their capital and having a Sassanid monarch assassinated. Yet Heraclius lived to see his spectacular success undone by the Muslim conquests of Syria, three Palaestina provinces, Egypt, and North Africa which was considerably facilitated by religious disunity and the proliferation of heretical movements (notably Monophysitism and Nestorianism) in the areas converted to Islam.