Granted a royal charter by the English King Edward II in 1334, Kinsale became a major port trading in wine and salt throughout the 15th century, and was also a provisioning port for the English navy.
In September 1601 English ships besieged a Spanish fleet anchored at Kinsale. Irish forces, which had appealed to the Spanish king to help them against the English, marched the length of the country to liberate the ships, but were defeated in the Battle of Kinsale on Christmas Eve. For the Catholic Irish, the immediate consequence was that they were banned from Kinsale; it would be another 100 years before they were allowed back in. Historians now cite 1601 as the beginning of the end of Gaelic Ireland.
After 1601 the town developed as a naval harbour, ship-building port and garrison town. In the early 18th century Alexander Selkirk departed from Kinsale Harbour on a voyage that left him stranded on a desert island, providing Daniel Defoe with the inspiration for Robinson Crusoe.
The town is also associated with the sinking of the Lusitania on 7 May 1915 off the Old Head of Kinsale – some of the bodies were brought ashore and buried here (many more are in Cobh), and the inquest into the disaster took place in Kinsale Courthouse. A memorial stands near the Old Head Signal Tower, which houses a Lusitania Museum.