The ground here was not virgin. An earlier medieval fortification known as Castle Ny-Parke had stood on the headland, and during the Siege of Kinsale in 1601 the Spanish garrisoned it as part of the wider 4th Spanish Armada that aimed to crack English rule in Ireland. Sir Richard Smyth led the assault that recaptured the castle for Charles Blount, Lord Mountjoy. The English then sat on the ruined site and considered what to do next. Within months of the Spanish surrender, the answer arrived: build a proper fortress here, in the new continental style, so that no foreign force could ever use Kinsale Harbour again. Construction began in 1602 to plans drawn by the military engineer Paul Ive. The fort was named for James I of England, who had inherited the throne from Elizabeth in 1603. It was completed by 1607.

What Ive designed was a hybrid: a four-sided stone half-bastioned tower at the centre, ringed by pentagonal earthworks raised to deflect cannon fire. The star pattern was the same logic that would soon shape Charles Fort across the harbour - low, angled walls that gave attackers no clean shot and gave defenders interlocking fields of fire from every face. James Fort represented the cutting edge of European military thinking when it was built. Within seventy years it would already be the old fort, eclipsed by something newer.

James Fort spent the 17th century changing hands as English politics turned. During the Williamite War in Ireland, Jacobite forces held both James Fort and Charles Fort across the water. In 1690 Williamite troops captured James Fort - not by storm so much as by accident, after an explosion in the fort's gunpowder stores tore the place apart and made resistance impossible. The fort never quite recovered. Once Charles Fort opened in 1682 with newer bastions and better artillery positions, James became the secondary post, the old fort. Its garrison shrank. By the 19th century, maps and travel writers described it as a ruin.

James Fort sits today as a National Monument, number 525 in the state register, managed by the Office of Public Works. Archaeological excavations through the late 20th and early 21st centuries - including a 1998 survey commissioned by Dúchas, then the Irish heritage service - have mapped what survives. The site is open and free, used by walkers, runners, and orienteers as much as by tourists. In 2016 An Taisce, the Irish National Trust, listed the fort in its at-risk category, noting that preservation works had helped but that long-term conservation planning was still needed. The earthworks have slumped. The central stonework leans. The Atlantic light still finds the angles of the bastions and makes the geometry visible. From the parapets you look across the narrow harbour mouth at Charles Fort, the new fort, sitting on its bluff. Two stars on two headlands, one ageing into a romantic ruin, the other into a heritage centre with a car park.