These coastal defences marked a shift away from castles, which were both military fortifications and domestic buildings, towards forts, which were garrisoned but not domestic; often the 1540s are chosen as a transition date for the study of castles as a consequence. The subsequent years also marked almost the end of indigenous English fortification design – by the 1580s English castle improvements were almost entirely dominated by imported European experts. The superiority of Scottish castle design also diminished; the Half Moon battery built at Edinburgh Castle in 1574, for example, was already badly dated in continental terms by the time it was built. The limited number of modern fortifications built in Ireland, such as those with the first gunports retrofitted to Carrickfergus Castle in the 1560s and at Corkbeg in Cork Harbour and built in the 1570s in fear of an invasion, were equally unexceptional by European standards.