Mortimer O'Sullivan (1791–1859) was a Church of Ireland clergyman, writer and member of the Orange Order.
He attended Trinity College Dublin, where he was elected a Scholar, graduated with an MA in 1812 and was ordained about 1816.
Throughout the 1830s and 1840s he was the chief ideologist of the Dublin University Magazine, a role he shared with his brother Samuel, also a convert and a cleric.
[1] His influence on the Church of Ireland was considerable, not so much for the originality as the blatancy of his views.
Captain Rock Detected (1824) Guide to an Irish Gentleman in Search of a Religion (1833) Case of the Protestants in Ireland Stated (1836) Theory of Development in Christian Doctrine (1846) Remains of Samuel O'Sullivan, D.D.