Sylvester O’Halloran, Irish surgeon with an abiding interest in Gaelic poetry and history, is born on December 31, 1728, at Caherdavin, County Limerick. For most of his life he lives and practises in Limerick and is later elected a member of the Royal Irish Academy (RIA).

O’Halloran is the third son of Michael O’Halloran, a prosperous farmer, and his wife Mary McDonnell. He is named after Sylvester Lloyd, the titular Catholic bishop of Killaloe (1728–39). His mother’s cousin, Sean Claragh McDonnell, teaches him much at an early age, including some Greek and Latin. He goes on to a Limerick school run by Robert Cashin, a Protestant clergyman, which is unusual at the time as the O’Hallorans are Roman Catholics during the difficult time of the Penal Laws.

O’Halloran and his brothers engage successfully in areas of life that work around the restrictions of the Penal Laws. Joseph becomes a Jesuit and holds chairs in rhetoric, philosophy and divinity at the Jesuit College at Bordeaux in France. George becomes a jeweler and in time a property-owner. O’Halloran goes to London to learn medicine at the age of 17, particularly studying the methods of Richard Mead, as well as the oculists Taylor and Hillmer. After further study at Leiden, and in Paris under the anatomist and academician Antoine Ferrein, he sets up practice as a surgeon in Limerick in early 1749.

O’Halloran writes several learned treatises on medical matters, and his fame is acknowledged by his membership of the RIA in 1787. He is a founder of the County Limerick Infirmary that starts with four beds in 1761 before moving to larger premises at St. Francis’s Abbey in 1765. The foundation stone of the original infirmary is now preserved in the Sylvester O’Halloran Post Graduate Centre at the Mid-Western Regional Hospital, Limerick.

While in France, O’Halloran is very impressed with the Académie Royale de Chirurgie, which had been founded in Paris in 1731 during the reign of Louis XV. He is subsequently instrumental in founding the Royal College of Surgeons in Ireland (RCSI), by writing its blueprint, Proposals for the Advancement of Surgery in Ireland, in 1765. In 1780, he is made an honorary member of the new Dublin Society of Surgeons and, when the RCSI receives its charter in 1784, is again elected an honorary member, equivalent to a Fellowship today.

As well as his scientific knowledge, O’Halloran’s interest in the arts begins with his collection of Gaelic poetry manuscripts and this leads on to an interest in Irish history. Given his background, he argues to validate the pre-Norman history of Ireland which had often been dismissed as a period of barbarism.

O’Halloran’s correspondents include Edmund Burke on early history. With Charles O’Conor of Bellanagare he discusses James Macpherson‘s translated version of Ossian and advises him about an eye complaint.

In 1789, Charlotte Brooke publishes the first English-language compendium of Irish poetry, the seminal “Reliques of Irish Poetry”, giving full due to O’Halloran for lending her his manuscript collection and for having written the essential history underlying her anthology.

In 1752, O’Halloran marries Mary Casey of Ballycasey, County Limerick, and they have four sons and a daughter. Their homes are in Change Lane and then on Merchants’ Quay. One of their sons is Major-General Sir Joseph O’Halloran, the father of Thomas Shuldham O’Halloran, after whom the Adelaide, South Australia suburb of O’Halloran Hill is named. Mary dies in 1782.

After a stroke, O’Halloran is infirm and confined to his chair for some time before his death on August 11, 1807, at his home on Limerick’s Merchant Quay. His is buried at St. Munchin’s graveyard at Killeely, which is now a suburb of Limerick.

Though politically restricted in his life by the Penal Laws, O’Halloran helps establish the county Infirmary, is elected President of the city’s Free Debating Society in 1772 and is elected to a committee in 1783 that examines the River Shannon navigation. Appropriately, a Limerick bridge over the River Shannon has been named after him.