Kings were an institution ancient long before the Medieval period came along. Put simply, the king was the hereditary or elected (by the nobility) ruler (usually absolute) of an area and its people. The Romans had abandonded kings for a republican form of government in the 5th century BC. Over several centuries their system evolved towards a democacy but never quite made it. In the end they more or less gradually re-introduced the monarchy during the first three centuries of the Christian Era, in the form of a "president (Consul) for life." Since the Romans had such an ancient distaste for kings, it was not until the 3rd century that their emperor was considered a kingly fellow, rather than just the "first citizen" of Rome (albeit the sort of fellow no one said "no" to.). The Germanic tribes had gradually introduced kings during the same period, by giving their tribal chieftans more power and the more imposing title. Both the Roman emperors and German kings were pagan institutions and, like most ancient kings their power was justified in part by the king claiming (and few were foolish enough to dispute him) a special relationship with the gods. Roman emperors became Christian in the 4th century, and the German kings began doing so about a century later. The Christian church handled the religious aspect by "annointing" kings in the name of God and preaching that the king's powers were blessed by God and should be respected. This was the "Divine Right of Kings " angle and it persisted until the 18th century in most of Europe. Of course, this gave the church some leverage in dealing with a king who abused the church or the people.