Ruins in Monmouthshire (Sir Fynwy)Ruins in Monmouthshire (Sir Fynwy)Tintern Abbey / Abaty TyndrynTintern was a Cistercian abbey, a Christian monastery or convent under the government of an Abbot or an Abbess, dating to the medieval period. Founded on the 9th May 1132 by Walter de Clare, Lord of Chepstow.