 St Tassac was a skilled artisan who made crosiers, patens, chalices, credences, shrines, and crosses for many of the churches founded by St Patrick, but is remembered primarily for the fact that he was selected by St Patrick to be with him in his last moments and to administer the Holy Viaticum to him.This event is chronicled in "The Martyrology of Donegal"; "Tassach of Raholp gave the Body of Christ to Saint Patrick before his death in the monastery of Saul".Since the 19th century, St Tassac has sometimes been confused, with Saint Assicus of Elphin, County Roscommon, who had the same types of skill and is said to have died in the same year, and with St Assam (or Assan).