The Fratres Cruciferi, or Crutched Friars, were a religious order who took their name from the crosses they bore, and whose house outside the Newgate served simultaneously as a hospital for the poor and infirm, a religious community for men and women, and, eventually, a minor point of civic infrastructure for the city's water supply. The layering of uses on this single patch of ground, across eight centuries, gives the site an unusual density of history that its present streetscape does almost nothing to advertise.

The institution was founded by a man named Ailred the Palmer, described by the antiquary James Ware as an Ostman, that is, one of the Norse Dubliners who had been settled in the city before the Anglo-Norman arrival. Ailred and his wife built the hospital on their own land outside the West Gate, at their own expense, sometime before 1188, when Pope Clement III granted it formal confirmation and substantial privileges. Both took monastic vows themselves, as did a number of associates who formed the founding community. The hospital was organised to receive men and women separately, and the register of the house suggests the sisters had a meaningful role in its management. By the reign of Edward III, according to Ware, 155 sick and poor were being maintained there alongside the chaplains and brethren. In 1308 the mayor of Dublin, John Decer, added a chapel of St Mary to the complex, though in 1316 both the church of St John and the chapel of St Magdalen were destroyed when citizens burned the Thomas Street suburbs to slow the advance of Edward Bruce's army. The house was dissolved in 1539; its church materials were granted to William Brabazon, Under Treasurer of Ireland, and as late as 1552 the monastery still contained a house with fifty beds for sick men. The church tower survived until around 1800, when it was pulled down, removing the last visible trace of what had stood there.

The site today sits on the north side of Thomas Street, where the Victorian Church of SS Augustine and John, with its prominent spire, occupies part of the original precinct. The distillery buildings cover much of the remainder. There is no on-site interpretation of the medieval history, and nothing marks where the watercourse once ran, the one that the Dublin Assembly Roll of 1457 records being leased to the priory for forty shillings a year, passing through what was then called Crockers Lane to supply the hospital's mill. Speed's 1610 map of Dublin, which is widely reproduced and accessible online, shows the watercourse to the west and north of the site and gives a clearer sense of the original layout than anything visible at street level today.