What is the X in X-mas?
1702; plural of humanity, which was used in English from late 15c. in a sense "class of studies concerned with human culture" (opposed variously at different times to divinity or sciences). Latin literae humaniores, they were those branches of literature (ancient classics, rhetoric, poetry) which tended to humanize or refine.
late 14c., "kindness, graciousness," from Old French humanité, umanité "human nature; humankind, life on earth; pity," from Latin humanitatem (nominative humanitas) "human nature; philanthropy, kindness; good breeding, refinement; the human race, mankind," from humanus (see human). Sense of "human nature, human form" is c.1400; that of "human race" first recorded mid-15c.