Soon, St. Dubricius was sent to seminary, where he excelled as a student and teacher, becomming known for his knowledge of modern and ancient law. He became ordained by St. Germainus as the first Bishop of Llandaff and Metropolitan of Cambria, and soon after founded a monastery on the banks of the Wye named Henllan. The new bishop taught there both secular and religious education for seven years. Faithful from all over Britain flocked to Henllan, which during his tenure held two thousand monks, including Ss. [[Thelian of Llandaff|Thelian]], [[Kingsmark]], and Samson.
Later he returned to Ynys Eurddil with
disciples to teach his native people. One evening an angel appeared to St. Dubricius in a dream, telling him to go round the island and find a sow with her pigs. There, said the angel, he was to lay a foundation for a monastery and oratory in the name of the Holy Trinity. The next day, St. Dubricius and his followers sought and found on the island a sow with her pigs, where they immediately set about construction, naming the place Mochros (''Moch'' - hogs, ''rhos'' - a place) and setting up residence, wherefrom St. Dubricius went about instructing and healing the sick. St. Dubricius was soon elevated to Archbishop, and given jurisdiction over all Wales.
During the season of Lent in 521, St. Dubricius visited [[St. Illtyd]] in Llandaff on the Feast of the Chair of Saint Peter to consecrate his disciple Samson, deacon, priest, and then bishop. During the ordination, both Ss Dubricius and Illtyd saw a white dove descend onto the head of St. Samson. The bishop was given charge over the daughter house of Ynys Byr as
abbott. However, having come there, Samson came to holy Archbishop, saying that great jealousies arose because of his receiving the leadership of the monastary. St. Dubricius prayed, and gave St. Samson his blessing, saying, "the Lord is wonderful among his saints", returning him to calm.
On one occasion, a nobleman by the name of Gwyddgeneu came before St. Dubricius on his knees to ask help his daughter Arganhell, who had become possessed by a daemon. She had to be bound feet and hands, otherwise the daemon would force her to try to drown in the water, engulf herself in flame, or to bite everything in sight. At their house, the Archbishop fell to the ground in tears, praying to the holy [[Apostle Peter]] for intercession, and at once the girl was cured. Becoming overjoyed, he devoted the rest of her life to God and joined a convent to serve the Lord.
===Retirement and Repose===
After 43 years of residence at Llandaff, St. Dubricius moved the See to the city of Caerleon, which was at that time the capital of Cambria and also at one time had been the ancient Metropolitanate.
Around 545, a Synod was called at the town of Brefi to condemn Pelagianism. Convening, St. [[Paulinus of Wales|Paulinus]] convinced St. Dubricius, the senior bishop to allow [[St. David of Wales]], then a minor abbot to address them. Consenting, and after hearing the abbot's words, the Archbishop to him.
He became a hermit and lived on the island of Bardley with his disciples, who worked the land. The island was called the Rome of Britain due to the dangerous passage by sea to it, its lush fertility, and its sanctity - having 20,000 confessors and martyrs buried there.
On Sunday, November 14, 612, St. Dubricius reposed and was buried on the island. In 1120 on
the 7th of May, his relics were removed by Bishop Urban of Llandaff and by the 23rd moved to Llandadd Cathedral, where there was a procession and the miracle of rain during a seven-week drought.
On June 2, Urban, along with his brother the Dean and his chaplain prepared the relics for reburial
by washing them in a basin, which was next to two other basins, full of the relics of Ss. Thelian and Oudoceus, who had been in descending order the next two Bishops of Llandaff. Placing the relics into their basins, the three men were astonished as the water began to bubble and become very hot. Bishop Urban took an arm bone of St. Dubricius and placed it into the water, watching as it began to move for an hour on its own. The three thanked God for the miracle and placed the relics in a tomb before the altar of the [[Theotokos]] in the monastary.
For the receiving of this relics, the Archbishop, Ralph of Canterbury, had given his blessing for the construction of a greater monastery in honour of Ss Peter the Apostle, and the Bishops Dubricius, Thelian, and Oudoceus of Llandaff.