After an initially peaceful start to John's reign, the king again began to extort money from the Jewish community and, with the breakdown in order in 1215, the Jews were subject to fresh attacks. Henry III restored some protection and Jewish money-lending began to recover. Despite this, the Jewish community became increasingly impoverished and was finally expelled from England in 1290 by Edward I, being replaced by foreign merchants. Christianity had been the official imperial religion of the Roman Empire, and the first churches were built in England in the second half of the 4th century, overseen by a hierarchy of bishops and priests. Many existing pagan shrines were converted to Christian use and few pagan sites still operated by the 5th century. The collapse of the Roman system in the late 5th century, however, brought about the end of formal Christian religion in the east of England, and the new Germanic immigrants arrived with their own polytheistic gods, including Woden, Thunor and Tiw, still reflected in various English place names. Despite the resurgence of paganism in England, Christian communities still survived in more western areas such as Gloucestershire and Somerset. The movement towards Christianity began again in the late 6th and 7th centuries, helped by the conversion of the Franks in Northern France, who carried considerable influence in England. Pope Gregory I sent a team of missionaries to convert King Æthelberht of Kent and his household, starting the process of converting Kent. Augustine became the first Archbishop of Canterbury and started to build new churches across the South-East, reusing existing pagan shrines. Oswald and Oswiu, kings of Northumbria, were converted in the 630s and 640s, and the wave of change carried on through the middle of the 7th century across the kingdoms of Mercia, the South Saxons and the Isle of Wight. The process was largely complete by the end of the 7th century, but left a confusing and disparate array of local practices and religious ceremonies. This new Christianity reflected the existing military culture of the Anglo-Saxons: as kings began to convert in the 6th and 7th centuries, conversion began to be used as a justification for war against the remaining pagan kingdoms, for example, while Christian saints were imbued with martial properties. The Viking invasions of the 8th and 9th centuries reintroduced paganism to North-East England, leading in turn to another wave of conversion. Indigenous Scandinavian beliefs were very similar to other Germanic groups, with a pantheon of gods including Odin, Thor and Ullr, combined with a belief in a final, apocalyptic battle called Ragnarok.