In the year AD 580, St Aidan crossed the Irish Sea from St Davids in Pembrokeshire (where he had been studying as St David’s favourite pupil) to Rosslare in County Wexford. Eighteen years later, he established a new monastery at Ferns, in the same county. This grew to become one of south-east Ireland’s most important settlements, a seat of royal power and the site of an Augustinian abbey. Little was known about the early history, however, until the Irish Archaeology Field School launched a major research project in June 2021. With commendable speed, the first fruits of that research have just been published, as Chris Catling reports.