While living in seclusion at Old Connell on the River Liffey in what is now Newbridge Conleth was persuaded by Saint Brigid to make sacred vessels for her convent.

According to Brigid's biographer, Cogitosus, a community of monks grew up which, under his guidance, excelled in the making of beautiful chalices and other metal objects needed in the church, and in the writing and ornamentation of missals, gospels, and psalters.

[2] The Diocese of Kildare appears to have been founded around 490, by Conleth who, with the assistance of St. Bridget, then presiding over the monastery, erected the cathedral and became first bishop.

Every year on the Sunday after St Conleth's Day a pilgrimage takes place from the parish church in Newbridge to Old Connell, about two miles outside the town.

[5] His tale and community are briefly described in Sabine Baring-Gould's "A Book of Cornwall"[6] (now in the public domain,) in which his name is spelled "Conlaeth."