Complex sentence: The early Wesleyan societies adopted English names, and not Greek ones; but Eclectic quickly adopted a motto the Greek initials of which are Phi Nu Theta and the society operated under both names.
Split into simpler sentences: The early Wesleyan societies adopted English names, and not Greek ones. But Eclectic quickly adopted a motto the Greek initials of which are Phi Nu Theta and the society operated under both names.