Background
He was the son of Sir James Donnellan, Chief Justice of the Irish Common Pleas and grandson of Nehemiah Donnellan, Archbishop of Tuam. His mother was Sarah Wheeler, daughter of Jonah Wheeler, Bishop of Ossory.
He was the son of Sir James Donnellan, Chief Justice of the Irish Common Pleas and grandson of Nehemiah Donnellan, Archbishop of Tuam. His mother was Sarah Wheeler, daughter of Jonah Wheeler, Bishop of Ossory.
He graduated from Trinity College Dublin in 1666.
Though he had originally intended to become a soldier, he resolved on a legal career instead, and entered Middle Temple in 1669. He was an exceptionally unruly student, being fined for breaking doors and gambling at Christmas. He was called to the Irish Bar about 1672 and became Commissioner of Revenue Appeals in 1677.
After the Revolution of 1688 he lived for a time in England.
He was appointed Prime Serjeant on 29 December 1692 and represented the borough of Galway in the Irish House of Commons from 1692 to 1693. In 1693 he was also made Recorder of Dublin.
He was raised to the bench as a Puisne Baron of the Irish Court of Exchequer in 1695, and on 31 December 1696 was one of the Commissioners of the Great Seal of Ireland until the appointment of John Methuen as Lord Chancellor of Ireland in 1697. He became Chief Baron of the Exchequer on 27 December 1703, holding the office until his death.
In 1698 the Irish born writer and publisher John Dunton, on a visit to Dublin, gave a favourable verdict on the Irish judiciary, including Donnellan: "men whose reputation is such that no one complains of them".
Anne is remembered as the friend of most of the leading Irish writers of her time, and for founding the Donnellan Lectures at Trinity College Dublin. Katherine married Robert Clayton, Bishop of Cork and Ross. She may well have come to regret his preferment, as his religious opinions were so unorthodox as to raise doubts as to whether he was a Christian at all.
Horace Walpole said unkindly that his writings seemed calculated to destroy anyone"s faith, and only his death averted an inquiry by his fellow bishops into his fitness for office.