Law, John (1745–1810), Church of Ireland bishop, was born in Greystoke, Carlisle, Cumberland (Cumbria), eldest son of twelve children of Edmund Law (1703–97), bishop of Carlisle, and his wife Mary Christian (d. 1772). He was educated at Charterhouse and Christ's College, Cambridge, where he graduated BA (1766), MA (1769), and DD (1782). He showed a talent for mathematics and graduated second wrangler in the mathematical tripos and senior-class medallist. He was appointed a fellow of Christ's College (1772) and took holy orders. In 1773 he was appointed prebendary of Carlisle, and in 1777 archdeacon. In 1782 he went to Ireland as chaplain to William Henry Cavendish Bentinck (qv), 3rd duke of Portland, lord lieutenant of Ireland. That year he was appointed bishop of Clonfert, proceeding to the dioceses of Killala (1787) and Elphin (1795). He was one of the original members of the RIA (founded in 1785) and founded prizes for the study of mathematics at Dublin University.
Taking a keen interest in protestant education in Ireland, he preached a sermon at Christ Church cathedral, Dublin, in April 1796, celebrating the work of the Incorporated Society for Promoting English Protestant Schools in Ireland. However, he despaired of converting the catholic majority to protestantism and contented himself with ‘circulating among them such catholic literature as might elevate their morals and manners’ (cited in Malcolmson, 492). Law was known as a friend of the English theologian William Paley (1743–1805), and for his tolerance to catholicism (which earned him a reprimand from the Church of Ireland historian, Richard Mant (qv)). He was also known as a man of character and courage: he faced down several local disturbances while bishop of Killala. During the 1798 rebellion he fortified his palace and, by resisting the insurgents and rallying the gentry in the area around Elphin, probably saved the lives and properties of many protestants in Co. Roscommon. In 1800 he was one of the leading protestors among Church of Ireland clergy against the tithe agistment bill, which confirmed the prohibition of the payment of tithe on pasturage as part of the act of union settlement.
He died 18 March 1810 at St Stephen's Green, Dublin, and was buried in TCD chapel. He married (17 January 1782) Anne (d. 13 March 1813), daughter of the Rev. William Plaskett and widow of John Thomlinson of Carlisle; they had no children.