Born to the ducal family of Ravenna, Romuald entered the Benedictine abbey of San Apollinare in Classe as penance after witnessing his father kill a man in a duel. He found the monastery's discipline too lax and left for a hermit's life in the Pyrenees, then returned to Italy and spent the rest of his life founding small communities of hermits and reforming existing monasteries — a network that eventually became the Camaldolese Order.
His great foundation, the Sacro Eremo di Camaldoli, was established around 1023 in the high Casentino forest above the Arno. The 'Brief Rule of St. Romuald' — addressed in his Life by Peter Damian — distills his teaching: 'Sit in your cell as in paradise; cast all memory of the world behind you; watch your thoughts as a good fisherman watches for fish.'
His five Polish disciples — Benedict, John, Matthew, Isaac, and Christian — were murdered together in 1003 (the Five Holy Polish Brothers), and his other disciple Bruno of Querfurt died in 1009. Peter Damian, who entered Camaldolese reform after Romuald's death, became his great hagiographer and his Doctor-of-the-Church spokesman.