The still-sizeable Byzantine Empire, Rome‘s direct continuation, survived in the Eastern Mediterranean and remained a major power. Secular law advanced greatly by the Code of Justinian. In the West, most kingdoms incorporated extant Roman institutions, while new bishoprics and monasteries were founded as Christianity expanded in Europe. The Franks, under the Carolingian dynasty, briefly established the Carolingian Empire during the later 8th and early 9th centuries. It covered much of Western Europe but later succumbed to the pressures of internal civil wars combined with external invasions: Vikings from the north, Magyars from the east, and Saracens from the south.