What makes this particular well worth pausing over is what it no longer does. Once a year, on the 12th of June, people would gather here for a pattern, the traditional Irish form of devotional assembly at a holy well, combining prayer with social ritual. That practice was abolished in the aftermath of the 1798 rebellion, and the well has shown no evidence of veneration since. It appears on the Ordnance Survey six-inch maps of both 1839 and 1903, named in gothic lettering on each, which is the cartographic convention reserved for antiquities and places of historical significance. The lettering outlasted the living tradition it was meant to mark.

The well takes its name from St. Caomhán Santleathan, a figure whose epithet is thought to mean something like "wide saint," though the precise sense of that is not entirely clear. He is credited with founding the first church at Ardcavan, the remains of which lie roughly 200 metres to the south-south-west. His genealogical connections, as recorded in hagiographical sources, are unusually tangled. He was associated with the Corca Ólaim and with St. Bréanainn of Birr, and also with the Uí Bhairrche of Magh Ailbhe in Carlow. Through his mother, Caoimgheall, daughter of Ceinnfhionnán, he was a half-brother of Caoimhghin of Glendalough, the saint more widely known in anglicised form as Kevin. The scholar John O'Donovan noted the pattern date around 1840, and the hagiographer Pádraig Ó Riain records that St. Finnian of Clonard in Meath is said to have stopped at Ardcavan while travelling to Wales, suggesting the site sat on an early ecclesiastical route of some significance. These connections place a modest, concrete-capped spring within a surprisingly wide network of early Irish sanctity.