TRINITY, HOLY. The doctrine of the Holy Trinity —the Trinity in Unity, and Unity in Trinity—is one of the profound mysteries of Christian doctrine. It is a doctrine which was formulated by the Church when it became necessary to construct Symbols, Creeds, or Con fessions. It was one of the fruits of doctrinal develop ment. Dr. F. C. Conybeare thinks that both the name and the idea of a divine Trinity were derived from an Alexandrine source, " for Philo taught that the divine being or nature is a three-in-one and one-in-three, and two of the persons with which he fills up his formula— namely, the king and father, and the son or Logos—are identical with those which Christian orthodoxy put for ward in this scheme." In any case, the doctrine was first elaborated in the Creeds. In the Nicene Creed (325 A.D.) Jesus Christ is said to be " of the substance (ek tes ousias) of the Father, God of God, Light of Light, Very God of Very God, begotten, not made, consub stantial (homoousion) with the Father." In the Constan tinopolitan Creed (3S1 A.D.) He is said to be " Begotten of His Father before all worlds, God of God, Light of Light, very God of very God, Begotten, not made, being of one substance (homoousion) with the Father." The Holy Ghost is said to be " The Lord; and the Giver of Life, Who proceedeth from the Father, Who with the Father and the Son together is worshipped and glorified, Who spake by the Prophets." The Council of Chalcedon
(451 A.D.) confirmed the Creeds of the Councils of Nicaea and Constantinople. The Creed which defined the doctrine of the Holy Trinity most fully was that com monly called the Creed of St. Athanaslus. He was not the author. It seems to have been called after him because it embodied, or was supposed to embody, his teaching. It really belongs to the sixth, seventh, or eighth century. Here the Catholic Faith is said to be this : " That we worship one God in Trinity, and Trinity in Unity, neither confounding the Persons, nor dividing the substance." We are forbidden by the Catholic Religion to say that there are three Gods or three Lords. There are not three Lords, but one Lord. " And in this Trinity none is afore or after other, none is greater or less than another : but all the three Persons are co-eternal together and co-equal." See The Definitions of the Catholic Faith, and Canons of Discipline, Oxford, 1874; C. A. Henrtley, On Faith and the Creed, 1889; Cath. Diet.; F. C. Conybeare,