The former bishopric of Mâcon was located in Burgundy.
The city of Mâcon, formerly the capital of the Mâconnais, now of the Department of Saône-et-Loire, became a civitas (Celtic tribal 'city state') in the 5th century, when it was separated from the Æduan territory. Christianity appears to have been introduced from Lugdunum (present Lyon) into this city at an early period, and Hugh, Archbishop of Lyon, in the eleventh century, would call Mâcon "the eldest daughter of the Church of Lyon".
The bishopric, however, came into existence somewhat later than might have been expected: in the latter part of the 5th century it was still a Bishop of Lyon who brought relief to the famine-stricken people of Mâcon. At the end of that same century Merovingian king Clovis's occupation of the city both foreshadowed the gradual establishment of Frankish supremacy, accompanied by a decline in Arianism in the see. Duchesne thinks that the bishopric of Mâcon, suffragan of Lyon, may have originated in an understanding between the Merovingian princes after the suppression of the Burgundian kingdom.
The first bishop historically known is St. Placidus (538-55). The authentic list of his successors, as reconstructed by Duchesne, comprises several bishops venerated as saints: St. Florentinus (c. 561); St. Cælodonius, who assisted at the Council of Lyon in 570; St. Eusebius, who assisted at two councils, in 581 and 585. Tradition adds to this list the names of St. Salvinius, St. Nicetius (St. Nizier), and St. Justus, as bishops of Mâcon in the course of the sixth century. Among other bishops of later date may be mentioned St. Gerard (886-926), who died in a hermitage at Brou near Bourg-en-Bresse, and Cardinal Philibert Hugonet (1473–84).