1502, "to make into one," from M.Fr.
unifier (14c.), from L.L.
unificare "make one," from L.
uni- "one" (see
uni-) + root of
facere "to make" (see
factitious).
Unification is attested from 1851; the
Unification Church was founded 1954 in Korea by Sun Myung Moon.
Unified is attested from 1862.
Unified (field) theory in physics is recorded from 1935.