Cronin, Edward (1801–82), missionary, was born in Cork city, son of a Roman Catholic father and protestant mother whose names are unknown; he had cousins whose names were Drury. He came to Dublin c.1826 to train as a doctor at the Meath Hospital and was at first welcomed by Independent congregations there, but his refusal to become a member of any particular church caused such scandal that he was ostracised. He spent Sunday mornings in hiding, sometimes in a hayfield, to avoid further disgrace, and was presently joined in prayer and scripture reading by Edward Wilson, the Dublin secretary of the Bible Society; together they came to reject many aspects of contemporary protestant belief, including the need for an ordained ministry. Others were attracted to worship in Cronin's house in Lower Pembroke St., Dublin, and about 1828 they joined John G. Bellett (qv), John N. Darby (qv), and others to become together the nucleus of the movement later known as the Plymouth Brethren.
In 1830 Cronin's wife (name unknown) died after the birth of a daughter, but he set off the same year with the child, his mother, his sister Nancy, John Vesey Parnell (1805–83), and another man, to attempt to join Anthony Norris Groves (1795–1853) in his missionary work in Baghdad. They were detained fifteen months in Aleppo, where Parnell and Nancy Cronin married. She and her mother died just before the party joined Groves in June 1832; the fate of Cronin's infant daughter is unknown. Despite these sorrows, privations, and the lack of success, Cronin spent another five years in missionary work in Baghdad and India before returning to London. He supported Darby in the ruptures that led to the establishment of the Exclusive Brethren after 1847, but in 1879 he was himself excluded from fellowship by this group, who resented his support for a dissident party at Ryde on the Isle of Wight. He married (28 May 1838) Frances, daughter of Sir John Kennaway, and they had three sons and three daughters together. Cronin died 1 February 1882 in Brixton, London.