In the early part of the period, the Roman province of Gaul gives way to the Frankish kingdoms, led for some 250 years by the Merovingian kings. Even under the Merovingians, the region remains recognizably Roman, preserving Roman administrative structures, language, learning, and many artistic practices. Christianity assumes ever greater importance as the nobility converts, founding large numbers of monasteries. The network of churches and monasteries built in the Merovingian period provides Charlemagne with an administrative infrastructure that will allow him to create his great empire in the ninth century. Charlemagne’s descendants, known as the Carolingians, will rule the region until almost the end of the period. Metalwork remains an important art form throughout the period. Highly accomplished examples of ivory carving and manuscript painting emerge under Carolingian rule. Though relatively few survive, many stone buildings—particularly in the form of churches, monasteries, and palaces—are built.