Trinity Sunday
Hymn 135.
Holy, Holy, Holy! Lord God Almighty!
¶Choose your part under Play voice to hear it alone, or let all four sound and sing yours. Concert key moves the whole hymn up or down to suit your voice.
Opening the music…
The Words
1Holy, Holy, Holy! Lord God Almighty!
Early in the morning our song shall rise to Thee:
Holy, Holy, Holy! merciful and mighty;
God in Three Persons, Blessèd Trinity!
2Holy, Holy, Holy! all the saints adore Thee,
Casting down their golden crowns around the glassy sea;
Cherubim and Seraphim falling down before Thee,
Which wert, and art, and evermore shalt be.
3Holy, Holy, Holy! though the darkness hide Thee,
Though the eye of sinful man Thy glory may not see,
Only Thou art Holy: There is none beside Thee
Perfect in power, in love, and purity.
4Holy, Holy, Holy! Lord God Almighty!
All Thy works shall praise Thy Name, in earth, and sky, and sea:
Holy, Holy, Holy! merciful and mighty;
God in Three Persons, Blessèd Trinity! Amen.
The Page It Came From

Where It Comes From
Read note by note from Hymns Ancient and Modern (Novello, London, 1861), and checked against the printed page. See that page in the scan of the book at the Internet Archive: open the page.
First published in London in 1861. Every tune, harmony and text in it was printed by 1861, so all its writers died long before 1966, and the book is out of copyright in India and the USA.