<p>John Stearne was the first Regius Professor of Medicine in Trinity College Dublin and founded the Fraternity of Physicians of Trinity Hall that later became the Royal College of Physicians in Ireland. He was born in Ardbraccan, County Meath in 1624 and was a great nephew of the Archbishop of Armagh and renowned scholar James Ussher who was his patron. He entered Trinity College in 1639 and was elected Scholar in 1641, before fleeing Dublin at the outbreak of the Confederate Wars later that year. He moved to Cambridge and studied medicine in Sidney Sussex College. After a short period practicing medicine in Bedfordshire, he returned to Trinity in 1651 and was appointed Professor of Medicine and College medicus. He later also became Professor of Hebrew and Professor of Law. He wrote six books and became a Senior Fellow of the College. In 1654, he established the Fraternity of Physicians with some other Dublin physicians in a disused building on Trinity Street. Stearne resigned his Fellowship and Professorship in 1659 but had them restored by 1662 following the Restoration of the King Charles II. The Royal College of Physicians of Ireland received its first royal charter in 1667. Stearne died in 1669 at the age of 44. This paper, written to celebrate the quatercentenary of his birth, discusses Stearne’s life and achievements in more detail particularly in the context of the political turmoil of the age and the important role of his extended family in the important events that occurred.</p>