The ruins of this Cistercian abbey merge with the stones of Burren. Saint Mary of the Fertile Rock was founded around 1180 by Donal Mór O'Brien or, more likely, by his son Donat. The choir and the chapels of the transept have finely sculptured capitals and beautiful vaulting. This was the setting for Yeats' first work The Dreaming of the Bones . The northern side of Turlough Hill (282 m) bears the ruins of three 12C churches.