Born: July 19, 1735, at the family estate of Dangan Castle, County Meath, Ireland.
Died: May 22, 1781, Kensington, London, England.
Buried: Grosvenor Chapel, South Audley Street, London, England.
Garret was the son of Richard Wesley, 1st Baron Mornington, and Elizabeth Sale, and husband of Anne Hill.
He showed talent on the violin from early childhood, and soon began composing his own works.
His son Arthur, the first Duke of Wellington, who defeated Napoleon at Waterloo, was the only one of his children to inherit some of his musical gift. Another of his descendants is Queen Elizabeth II of Britain.
He attended Dublin University, and was elected its first Professor of Music in 1764.
The family name was changed to Wellesley in 1798.
As a composer, he is remembered chiefly for glees such as Here in cool grot (lyrics by William Shenstone), a double Anglican chant, and his Chant in E, from which the tune Mornington is arranged.