The monastery of Dumio is a former monastery of the early Christian period, which is located in the district of Dumio, which is included in the district of Braga. Originally the site of the monastery was a Roman Villa. On its territory there was a Basilica built by the suebi, a Germanic tribe. A primitive Church was built by the king of the suebi, Horaria, to celebrate the recovery of his son. During this king began the conversion of the suebi in Christianity.

In the VI century on this site for a monastery was founded, headed by Martin Brisky, one of the most prominent Church leaders Portugal in the early middle ages. Martin Brisky is also one of the patron saints of the Archdiocese of Braga and played an important role in the conversion of the suebi in Christianity. Together with the monastery was founded Autonomous diocese of Dumio.

The monastery of Dumio is the first monastery that appeared on the territory of the Iberian Peninsula. Martin Brisky founded several monasteries, the monastery of Dumio is the most famous among them. After the death of Martin Brisky was buried in the Cathedral of the monastery of Dumio. In the IX century, when Brahe was approaching Muslim army, the relics of the Saint were transferred to Mondonedo, and after the victory of the Christians over the Muslims, the relics were returned to Dumio. Approximately to the tenth century religious center, another name for the diocese of Dumio, was abandoned.

In the late twentieth century archaeological excavations on the site of the monastery of Dumio, during which it became clear that some time in the diocese there was still a parish Church, but not very long. Excavations have revealed pottery and coins from the middle ages, glass ware, amphorae and decorative mosaics of the Roman period. It is interesting to look at artifacts such as the lid of the sarcophagus, fragments of the Foundation pillars, arches and more.

The ruins of the monastery are located around Lugar da Igreja, on the square, which is also the parish Church of Dumio. Here are the Church of St. Martin Dubickogo, the chapel of the rosary and rear patio where there was a pool cashier do Assento. During excavations in Dumio were detected structures such as a Roman Villa and baths, the remains of the Basilica, necropolis of 12 graves, once surrounded granite slabs.