Adesto sancta Trinitas. [Holy Trinity .] The authorship of this short hymn on the Holy Trinity is unknown. Its earliest form is in a manuscript of the 11th century, in the British Museum (Vesp. D. xii. f. 1156) printed in the Latin Hymns of the Anglo-Saxon Church, 1851, p. 161. Amongst the English Breviaries it is in those of York, Hereford, and Sarum; on the Continent, those of Mainz and Basel; and also in those of the Orders of the Carmelites, Dominicans, and Fratres Humiliati; but with varying texts. In Mone, i. p. 10, the text is given together with references to manuscripts, and notes on the text; the oldest manuscript dating from the 14th century. He also gives two refrains which are sometimes associated with the hymn. Daniel, i. No. 304, gives only the first four lines with a reference to Cassander; but in iv. p. 234, he gives the full text as in Mone, together with Mone's references. It is also in Neale's Hymni Ecclesia, 1851, p. 157; Hymnarium Sarisburiense. 1851, p. 115; the Domin. Hymn Book, &c. [Rev. W. A. Shouts, B.D.]
Translations in common use:—
1. Be present, Holy Trinity; Like Splendour, &c. By J. M. Neale. Appeared in the Hymnal Noted, 1852, No. 35, in 5 stanzas of 4 lines, and again in later editions. In 1867 it was repeated, unaltered, in the People's Hymnal, No. 161, and in the Hymnary, 1872, No. 337.
--Excerpt from John Julian, Dictionary of Hymnology (1907)