According to this Life, Gildas had been sent by his parents to study in the island monastery of Hildutus, where "a great number of the sons of the nobles were taught". Gildas encouraged his master to pray for the improvement of this small island and in due course its area was extended and its fertility improved. The scribe says that in his day the island was known as Llanilltud - the Llan of Illtud. Other ancient texts make it clear that the monastery was on a small island near Dyfed and that the island was also known by the name of Pirus or Pyrus. When Giraldus Cambrensis described his home in Pembrokeshire he mentioned the nearby "island of Caldei, which the Welsh call Enis Pir".  

Caldy Island is today home to a monastic community, sucessor to the ancient Celtic christian foundation. Present day monks support their community partly by the sale of products made on the island, more fertile since the student days of St. Gildas.