Roman imperial rule continued in the East, and the Byzantine-Sasanian wars continued. In the 6th century, the reign of Justinian the Great led to the fall of the Ostrogoths and the Vandal Kingdom and their reincorporation into the Empire, when city of Rome and much of Italy and North Africa returned to Roman control, and though most of Italy was soon part of the Kingdom of the Lombards, the Roman Exarchate of Ravenna endured, ensuring a Byzantine Papacy. The construction of Hagia Sophia, greatest example of Byzantine architecture, and the plague of Justinian, first outbreak of the centuries-long first plague pandemic both took place under Justinian and his Persian counterpart Khosrow I. At Ctesiphon, the Sasanians erected the Taq Kasra, the colossal iwan of which is the largest single-span vault of unreinforced brickwork in the world and the triumph of Sasanian architecture. In the 7th century the disastrous Byzantine-Sasanian War of 602-628 and the campaigns of Khosrow II and Heraclius facilitated the emergence of Islam in the Arabian Peninsula during the lifetime of Muhammad. Subsequent Muslim conquests of the Levant and Persia, which overthrew the Sasanian Empire and permanently wrested two thirds of the Eastern Roman Empire's territory from Roman control, forming the Rashidun Caliphate. The Byzantine Empire under the Heraclian dynasty begins the middle Byzantine period, and together with the establishment of the later 7th century Umayyad Caliphate, generally marks the end of late antiquity.