Tomb of the Unknowns?

Ann Coulter writes: "When did "B.C." (before Christ) and "A.D." (anno Domini, "in the year of the Lord") get replaced with "BCE" (before the common era) and "CE" (common era)? "Withdrawal" is "redeployment," "liberal" is "progressive," and "traitorous" is "patriotic."

Words are everything. Words are the roadmap for our thoughts. To control a people - control the language.

I have an additional question - when did "Tomb of the Unknown Soldier" become "Tomb Of The Unknowns"

And just what are unknowns anyway? Unknown what?