Athassel Priory is the largest medieval priory in Ireland, stretching over a four acre site. The priory dates back to the late 12th century when it was founded by the Augustinians under the patronage of William de Burgh. William's grandson Hubert de Burgh, (or Burgo) later the Bishop of Limerick, was prior at Athassel c. 1221. The original buildings were altered and renovated over the next 300 years.