It was a term which made the transition easy from Jewish Monotheism to Christian trinitarianism.
"The Expositor's Bible: The Gospel of St. John, Vol. I"
Marcus Dods
At first a Romanist, he resigned that faith for Calvinism, but gradually advanced to Anti-trinitarianism, which he defends in two letters to Gregorio Pauli, dated Austerlitz 1564 and 1565. Beza says that Alciati deserted the Christian faith and became a Muhammadan, but Bayle takes pains to disprove this.
"A Biographical Dictionary of Freethinkers of All Ages and Nations"
Joseph Mazzini Wheeler
Mr. D'Arcy's trinitarianism is decidedly more Greek than Latin.
"The Faith of the Millions (2nd series)"
George Tyrrell