The great fortress and walled town of Athenry played a vital role in the Anglo-Norman control of East Connaught. Construction of the castle can be dated to between 1235-41 and was undertaken by Meiler de Bermingham after being granted a charter by William de Burgo, the Anglo-Norman conqueror of much of Connaught. It comprises a particularly well-preserved first-floor hall standing isolated within a walled enclosure, which forms part of the town's mural defences. The bailey has been much restored, and there is a round tower at the south-east corner and fragments of another on the north-east. Excavations in 1989 did not resolve the problematic question of the exact location and nature of the entrance, which presumably lay in the south-west corner. The town's walls were begun in 1312 and considerable lengths can still be seen. Not long after the completion of their walls one of the bloodiest battles of medieval Ireland was fought outside the town between Phelim O'Connor, King of Connaught, and the Anglo-Normans. The defeat of the Irish was so decisive that the constant struggle with the O'Connors came to an end - a process that seems to have resulted in a decline in the importance and strength of the town. It fell an easy prey to Red Hugh O'Donnell in 1596 and never recovered from the damage he inflicted.