Xmas as a replacement for Christmas comes from Χριστός and usage in English dates back to the 1500s. Admittedly the use for Christian [sic] was a bit lazy, but

Xmas as a replacement for Christmas comes from Χριστός and usage in English dates back to the 1500s. Admittedly the use for Christian [sic] was a bit lazy, but I was not attempting to make any point. I enjoyed Helianthus' take on it though - goes to show whatever you say can be reinterpreted by analysts to provide a depth of meaning you never intended ;)