What is the X in X-mas?
mid-15c., "body of a person" (with regard to appearance), from Old French personage "size, stature," also "a dignitary" (13c.), from Medieval Latin personaticum (11c.), from persona (see person). Meaning "a person of high rank or distinction" is attested from c.1500 in English; as a longer way to say person, the word was in use from 1550s (but often slyly ironical, with suggestion that the subject is overly self-important).