Maguelonne (or Maguelon) was one of the "seven cities" that may have been the origin of the name for the region called Septimania. Septimania was the western region of the Roman province of Gallia Narbonensis, which passed under the control of the Visigothic kingdom in 462, when Septimania was ceded to Theodoric II, king of the Visigoths. The seven cities were today's Elne, Agde, Narbonne, Lodève, Béziers, Nîmes and Maguelone.
At first the stronghold of a Visigothic noble, on high ground protected by coastal lagoons, Maguelonne became the seat of a bishop. When the early history of Maguelone was compiled in 1583 by Abbé Gariel (Histoire des évêques de Maguelonne) he provided the see with an apostolic origin, as is de rigueur for any long-established bishopric of Late Antiquity throughout the three Gauls. The first historical bishop of Maguelonne assisted at the Council of Narbonne in 589; doubtless the Christian community was far older. In the 8th century the Almohad walis conquered the area, which was finally retaken by Charles Martel in 737, but the contests, which took decades, all but depopulated the region. The diocese was removed to Substantion, but Bishop Arnaud (1030-1060) returned it, rebuilt the destroyed sanctuary and constructed a bridge to link Maguelone to the "new district" of Villeneuve. The powerful and compact Romanesque cathedral of Saint-Pierre de Maguelone was constructed.
The local count retained the traditional Carolingian right of nomination of bishops: in 1085 Pierre, count of Substantion and Melgueil, offered himself as vassal of the Holy See and relinquished the right of nomination, and Innocent III transferred the feudal rights of the county to the bishop of Maguelonne in 1215, which gave the bishops the right to issue coinage The bishop, as well as the King of Aragon and the Count of Toulouse, authorized the coinage of Arabic money, not intended for circulation in Maguelonne, but to be sold for exportation to the merchants of the Mediterranean
With the expansion of trade in the revival of the High Middle Ages, Montpellier came to be the city for this region, first passing to the Crown of Aragon in 1204, then to that of France (1292 and 1349). In 1536 the see was finally transferred there
A sentimental and chivalric romance of the high-born Miguelonne and Pierre, the son of the King of Provence, who recognized each other in their old age after many heartbreaking separations, inspired a verse: Epistle by Clément Marot.