Christmas - The Word

The word "Christmas" is from the Middle English "Christemasse", and in Old English "Cristes mæsse". The compound meaning of these is "Christ's Mass" and was first used circa 1030 AD. "Cristes" is from Greek christos and "mæsse" is from Latin missa. In the early Greek testaments, 'X' is the first letter of Christ, which I guess some could use to validate their use of the spelling 'Xmas'. I'm sure that people using this form learned it from studying ancient Greek.