William Marsh (1775–1864) was a British priest in the Church of England and a writer of theological publications, in the 19th century.
He was moved by witnessing the sudden death of a young man in a ball-room and he decided to abandon a military career and become a cleric.
His father presented him to the united livings of Basildon and Ashampstead in Berkshire in 1802, when he resigned Nettlebed, but retained the curacy of St. Lawrence, which he served gratuitously for many years.
His attention was early called by Simeon to the subject of the conversion of the Jews, and in 1818 he went with him to the Netherlands to enquire into their condition in that country.
[2] Ill-health obliged him in 1829 to leave Colchester, and in October of the same year he accepted the rectory of St. Thomas, Birmingham, where from the frequent subject of his sermons he came to be known as 'Millennial Marsh'.
Early in 1837 he was appointed principal official and commissary of the royal peculiar of the deanery of Bridgnorth; and in 1839, finally leaving Birmingham, he became incumbent of St. Mary, Leamington.