According to tradition, the diocese of Braga dates back to the 3rd century, although historical confirmation dates back to the year 400. This makes it one of the oldest dioceses on the Iberian Peninsula. It is considered the center of the Christianization of Gallaecia, as the area in the northwest of Spain and the north of Portugal was called. When Rome's power was dissolved by invading Germanic tribes, Braga became the capital of the Suebi Kingdom from 409 to 584. Through the influence of Bishop Martin of Dumio, the Suebi converted to Catholicism around 550. Martin of Dumio had come to Gallaecia at this time and first founded a monastery in Dumio near Braga, became Bishop of Dumio in 556 and finally Bishop of Braga in 562. However, the Suebi Empire fell into Visigothic dependence and was incorporated into the Visigothic Empire in 585. In the period that followed, Braga's importance declined. After the conquest of the Iberian Peninsula by the Moors in 711–719, Braga lost its episcopal see in 716. As a result of the Reconquista, the reconquest by the Christians, the diocese of Braga was re-established around 1070. Bishop Dom Pedro, who was bishop of the diocese from 1071 to 1091 and the first archbishop, had a cathedral built, which was consecrated by Bernard of Toledo in 1089. At that time, however, only the eastern chapels were finished. The current cathedral was built on the site of an older religious building, possibly an earlier cathedral. Despite the restoration of the Braga diocese, the city did not manage to regain its former importance. Next to Toledo, which was declared the new metropolis by Urban II and was the residence of the Kingdom of Castile from 1087 and remained the capital of Spain until 1561, there was no place for Braga as a metropolis. Since Bishop Dom Pedro also received the pallium from antipope Clement III in 1091. The former capital Braga continued to lose its importance. Bishop Dom Pedro was deposed and banished to the monastery.
Since 1093, the county of Portugal was ruled by Count Henry of Burgundy, who, together with Bishop Geraldo de Moissac, was able to convince the Pope to restore Braga to an archbishopric in 1107. Construction work on the cathedral resumed and continued until the mid-13th century. Built in the 12th century, the building was built in the Burgundian Romanesque style of the Abbey Church of Cluny and influenced the construction of many churches and monasteries in Portugal. In the following centuries the cathedral was changed frequently. Today it therefore has a mixture of different architectural styles such as Romanesque, Gothic, Baroque and Manueline.
In 1905, Pope Pius X gave the cathedral the additional title of minor basilica.
Source: Wikipedia