According to tradition, the monastery was founded by Saint Patrick shortly after his arrival in AD 432; he landed via the nearby River Slaney and was granted a barn (Old Irish saball) by the local chieftain Dichu.

[1] Some time after 1130 Saul was refounded as an Augustinian priory of Canons Regular by Saint Malachy;[8] legend claims that he had a vision of the monastery before he constructed it.

a convent of religious monks, with their abbot, whom Maelmaedhog Ua Morgair, legate of the successor of Peter, had appointed at Sabhall-Phadraig, were expelled from the monastery, which they themselves had founded and erected; and they were all plundered, both of their books and ecclesiastical furniture, cows, horses, and sheep, and of every thing which they had collected from the time of the legate aforesaid till then.

[11][12]In 1289 or 1293, Nicholas Mac Mail-Issu discovered the remains of Saints Patrick, Colum Cille and Brigid of Kildare at Saul; he placed them in a shrine.

At the dissolution of the monasteries, the abbey, with two castles, a garden and land were granted to Gerald FitzGerald, 11th Earl of Kildare in 1542.

"[16] One wall of the Augustinian abbey remains, and a stone monastic cell (also called the "mortuary house")[15] in the old graveyard.