Trinity Sunday.--Trinity Sunday is a Festival of late institution, as the day on which it is observed was originally kept as the Octave of Whitsun Day. It was not until A.D. 1260 that it was first directed by the Synod of Aries to be observed by the whole Church as Trinity Sunday, although Thomas a Beckett is said to have instituted this Festival in England in {261} A.D. 1162, and reference is made to it as early as A.D. 834. The observance of this day is very significant and rounds out or completes the former commemorations of the year. As set forth in "Thoughts on the Services," "The Church's services have culminated; to-day they mount up to the Throne of the Godhead; for knowing the Son and the Holy Ghost, we know the Father also, and that these Three are not three Gods, but one God. The Church to-day celebrates the glory and majesty of God in His essence and in His works. In the word _Trinity_, she simply sums up what is revealed concerning Him,--that in Substance He is One, but in Persons, Three. . . . The Collect enables us to worship the _Unity_ which exists in the power of the Divine Majesty, even while we acknowledge the glory of the Eternal Trinity." Proper Lessons, Proper Psalms and Proper Preface in the Communion Office emphasize the importance of the Festival and mark it as one of the great days of the Church. The ecclesiastical color is white. Trisagion.--A Greek word meaning the same as _Ter Sanctus_, _i.e._, "Thrice Holy," but it is not used in the Greek Church for the same thing, but is the title of the respond used in the Reproaches and other services, namely, "Holy God, Holy and Mighty, Holy and Immortal, have mercy upon us." Triumphal Hymn.--The ancient name given to the Ter Sanctus, the hymn in the Communion office beginning, "Holy, Holy, Holy." Triumphant, The Church.--The Church in Heaven. (See CHURCH CATHOLIC.) {262} Tunicle.--A vestment worn by the Subdeacon or Epistoler at the celebration of the Holy Communion; somewhat similar to the Dalmatic worn by the Deacon or Gospeler, but shorter, narrower and not so elaborately embroidered. Turning to the East.--(See EAST, TURNING TO.) Twelfth Day.--A popular name given to the Feast of the Epiphany which occurs twelve days after Christmas. Many social rites and customs have long been connected with the evening of this Festival, which is commonly called "Twelfth Night." U Unction.--(See ANOINTING THE SICK.)