Dominic was born around 1000 at Cañas in Navarre to a noble Spanish family — a kinsman of St. Iñigo of Oña. Educated at the Benedictine Abbey of San Millán de la Cogolla (the principal medieval Navarrese-Riojan monastic centre), he became a monk there and rose to be prior under reform-discipline.
His opposition to the depredations of the Navarrese King García Sánchez III on the monastic lands produced his exile from Navarre around 1040 — he fled to Castile, where the reforming Castilian King Ferdinand I (1037–1065) welcomed him.
In 1041, Ferdinand I appointed Dominic as abbot of the decayed Abbey of San Sebastián de Silos (the principal medieval Castilian abbey, founded in the 7th century during the Visigothic period). For 32 years (1041–1073) Dominic governed Silos — rebuilding the decayed abbey-buildings, re-establishing the Benedictine discipline under Cluniac reform, and producing the characteristic late-11th-century Castilian-Cluniac monastic culture.
He became famous in the reconquest-era Spanish Catholic tradition for his ministry of negotiating the release of Christian captives held by the Moorish-Andalusian Muslim authorities — undertaking personal missions to the Moorish frontier, collecting ransom-money among the Spanish Catholic faithful, and personally redeeming hundreds of Christian captives over the decades of his ministry. The reputation as the hostage-redeemer of Catholic Spain established his cult as the principal Catholic patron of Christian prisoners and captives — the patronage that would underpin the late-12th-century foundation of the Mercedarian and Trinitarian orders of ransomers.
He died at the Abbey of Silos on December 20, 1073, and was canonized within three years by Pope Gregory VII in 1076 — among the earliest formal papal canonizations after the 993 Ulrich precedent.
The Abbey of Santo Domingo de Silos was rebuilt by his successors in the late 11th and early 12th centuries — producing the famous Romanesque cloister (c. 1085–1130), one of the principal Romanesque sculptural monuments of medieval Europe. The abbey survives in continuous Catholic Benedictine liturgical use today, famous as the community whose 1994 recording of Gregorian chant ('Chant') became a global commercial phenomenon (selling over 6 million copies, reaching No. 3 on the Billboard 200 album chart).