December 25th marks the birth of Jesus Christ, and is celebrated yearly as one of the most important holidays in Christian faith, after Easter. The origin of the date, December 25, is believed to have stemmed from theory that Christmas originated as a Christian substitute for pagan celebrations of the winter solstice. In 312 AD, the Roman Emperor Constantine I converted to Christianity, and church leaders made efforts to appropriate the winter-solstice holidays. They believed that the world was created on the spring equinox in late March, and therefore God would have conceived Jesus on that date. The Virgin Mary, pregnant with the son of God, would hence have given birth to Jesus nine months later on the winter solstice. The oldest existing record of a Christmas celebration is found in a Roman almanac that tells of a Christ’s Nativity festival led by the church of Rome in 336 A.D. From there, Christ’s Nativity celebration spread to Christian churches around the globe. In the 4th century, St. Nicholas of Myra, was said to visit children with gifts and admonitions just before Christmas. This story evolved into the modern practice of leaving gifts for children said to be brought by “Santa Claus,” or “Old Saint Nick,” a derivative of the Dutch name for St. Nicholas–Sinterklaas.