Dominic was born around 995 in Foligno, Umbria. The scandal of his youth — that his simoniacal father had purchased his priestly ordination from a corrupt bishop while Dominic was still a layman, the ordination being invalid — produced the extreme repentance that became the characteristic of his life.
He entered the eremitical life under St. Romuald's Camaldolese hermits, then settled at the Hermitage of Fonte Avellana in the Marche under the direction of St. Peter Damian (prior of Fonte Avellana 1043–1057, cardinal-bishop of Ostia 1057–1072) — the principal Italian eremitical centre of the mid-11th century.
Dominic became famous in the medieval Catholic ascetic tradition for the extremity of his penitential disciplines — most including: continuous wearing of an iron-mail shirt (lorica) next to his naked skin, which gave him the epithet Loricatus ('the Mailed'); use of multiple discipline-scourges (he invented the discipline-and-Psalter penitential exercise: reciting the entire Psalter while simultaneously scourging himself with both hands, one stroke per Psalm verse, producing the equivalent of 3,000 stripes per Psalter recitation; he was documented by St. Peter Damian as completing 100 Psalter-disciplines in a single Lenten season, producing the equivalent of 300,000 stripes); continuous standing (he would not sit even to eat); extreme fasting and sleep deprivation.
St. Peter Damian composed Dominic's Vita Beati Dominici Loricati (Life of Blessed Dominic the Mailed) — one of the principal extreme-ascetic hagiographical texts of medieval Western Catholicism, documenting Dominic's disciplines in vivid detail. Peter Damian cited Dominic as the classic exemplar of the private-discipline penitential practice that the Romualdine-Camaldolese reform was promoting against the hereditary clerical-and-monastic laxity of the pre-Gregorian-reform period.
Dominic Loricatus died at Fonte Avellana on October 14, 1060, having spent decades in the extreme penitential discipline that underpinned his reputation as the classic medieval extreme-ascetic saint.