The ruins off Patrickswell Lane, long assumed to mark the site of the Abbey and Hospital of St Mary d'Urso, turn out to belong to an entirely different religious community. Research published in 2019 by McHugh demonstrated conclusively that those remains are the church of the Augustinian friars, not the Crutched friars, and that St Mary d'Urso lies elsewhere, just outside the old West Gate, where it appears on the Newcomen map of 1657.

The abbey was founded by Ursus de Swemele sometime between 1206 and 1214 for the Crutched friars, also known as the Fratres Cruciferi, a religious order whose name refers to the cross they bore on their habit and whose mission centred on the care of the sick. The hospital served the poor and ill of Drogheda from that position outside the town walls, a deliberate placement that was typical of medieval hospitals, which were often sited at the margins of urban settlements. By 1377, the community had acquired a sufficiently complicated reputation that three of its friars and a chaplain were tried for assault, though all were acquitted. When Henry VIII's suppression of the monasteries reached Ireland in 1540, the property return for St Mary d'Urso made for an underwhelming picture on the surface: a dovecote and two orchards covering one and a half acres. But the same return also revealed that the house controlled substantial property within Drogheda itself, sixty acres at a place called Glasspistol, thirty acres at Carlingford, and further landholdings scattered across the county. The modest physical site belied a significant economic footprint. In 1557, the priory passed into the hands of Drogheda Corporation.