The Fourth Council of Toledo was held in 633. It was convened by Visigothic king Sisenand and took place at the church of Saint Leocadia in Toledo.
Probably under the presidency of the noted Isidore of Seville, the council regulated many matters of discipline, decreed uniformity of liturgy throughout the Visigothic kingdom and took stringent measures against baptized Jews who had relapsed into their former faith.
From the 5th century to the 7th century AD, about thirty synods, variously counted, were held at Toledo (Concilia toletana) in what would come to be part of Spain. The earliest, directed against Priscillianism, assembled in 400. The "third" synod of 589 marked the epoch-making conversion of King Reccared from Arianism to Catholic Chalcedonian Christianity. The "fourth", in 633, probably under the presidency of the noted Isidore of Seville, regulated many matters of discipline and decreed uniformity of liturgy throughout the kingdom. The Britonia of Galicia accepted the Latin liturgical rite. The "twelfth" council in 681 assured to the archbishop of Toledo the primacy of Hispania (present Iberian Peninsula). As nearly one hundred early canons of Toledo found a place in the Decretum Gratiani, they exerted an important influence on the development of ecclesiastical law.
The later synod of 1565 and 1566 concerned itself with the execution of the decrees of Trent; and the last council of Toledo, that of 1582 and 1583, was so guided in detail by Philip II that the pope ordered the name of the royal commissioner to be expunged from the acts.