The earliest celebrations of Christ's birth, that are known, were mentioned around 200AD. So celebrations are likely to have occurred in the second century. However, celebrating Christ's birth was not seen as highly important in those days. Many rejected the idea of a birthday celebration altogether. The prime focus was on Christ's life, crucifixion and resurrection. The December 25th date was observed as early as the third century and became more accepted throughout the fourth century as the Roman Empire converted to Christianity.