Máedóc (Áed, Áedán, Mogue) (d. 625/6), founder and bishop of Ferns, Co. Wexford, is patron saint of the diocese of Ferns and of Drumlane (Co. Cavan) and Rossinver (Co. Leitrim). Later tradition says that his name Áed was changed to the hypocoristic form Máedóc (Mo-Áed-óc meaning ‘my little Áed’) by members of the Ua Dubthaig family who fostered him. The name appears in various forms in the sources, and he is frequently confused with homonymous saints, many of whom are mentioned in the Irish martyrologies. He is described in the ‘Vita S. Davidis’ as ‘Maidoc qui et Aidanus ab infantia’, and in the ‘Acta S. Edani’ as ‘Edanus qui et Moedoc dicitur’. The Welsh genealogies of the saints call him Aeddan Foeddawg, the latter element of which is a reduplicate of Máedóc.
According to tradition, Máedóc was born around the middle of the sixth century on the crannog of Inis Brechmaige in Templeport lake in Co. Cavan. Like most Irish saints he is reputed to have been of royal lineage. His father, Sétnae, belonged to the Uí Moccu Uais of the Iargialla and was descended from Conn Cétchathach (qv). His mother, Eithne, was a granddaughter of Amalgaid, king of Connacht and grandson of Eochaid Mugmedón. He is reputed to have been a student of St Mo-Laisse (qv) (d. 564) of Devenish. A tradition that places him as a student of St David at Menevia in Wales is relayed in the Lives of Saints David and Cadoc (qv), and elsewhere in Welsh hagiographic tradition, but probably dates only from the eleventh century when his Life was taken to Wales by Sulien, bishop of St David's. According to his Life he returned to Ireland and landed on the Wexford coast at a place called Ard Ladrann (identified as the ‘moat of Ardamine’, townland of Middletown, parish of Ardamine). After spending some time in the territory of the Déisi, he moved into Uí Chennselaig, where he founded a church at Ferns toward the end of the sixth century. He is also credited with founding churches at Drumlane (Druim Lethan; Co. Cavan) and Rossinver (Co. Leitrim), and possibly at six other locations.
Máedóc is sometimes confused with another seventh-century saint of the same name whose feast-day is 11 April, Máedóc (qv) of Cluain Mór Máedóc (Clonmore, Co. Carlow). In the eleventh century, rivalry between two branches of the Uí Chennselaig dynasty based at Ferns and Clonmore resulted in the plundering of Clonmore (1040) by the Ferns branch led by Diarmait (qv) son of Donnchad Máel na mBó (qv) (king of Leinster 1042–72). The Life of Máedóc of Ferns was then rewritten in an attempt to boost the significance of Ferns and to overshadow the cult of Máedóc of Clonmore by transferring some of the acta of the Clonmore saint to the Ferns saint. It was also intended to associate Diarmait's remote ancestors with Máedóc of Ferns; it credits the seventh-century Brandub (qv) son of Eochu, overking of Leinster and an ancestor of Diarmait, with having presented the ground for the church at Ferns, and it plays up his role in the politics of the period. The revised Life is extant in a number of Latin versions.
In the twelfth century, the centre of the cult shifted from Ferns to Drumlane, reflecting the rise of the Ua Ruairc dynasty of the kingdom of Bréifne. The Lives associated with Drumlane are in Irish. They emphasise the northern aspects of the cult of Máedóc, and give an important role to Mo-Laisse of Devenish. For political reasons Drumlane eventually lost out to Rossinver, which became the centre of the cult in the fifteenth century.
In Leinster there are many church sites and holy wells dedicated to ‘St Mogue’, but some may relate to Máedóc of Clonmore. There are also a number of dedications in Pembrokeshire: Llanmadog, Llawhaden (Llanaedan), Capel Madoc, and the churches of Nolton, Haroldston West, and Solva S. Aidan. In addition, there are some Scottish dedications. The fourteenth-century chronicler John of Tynemouth records that the feast-day of Aidan was still kept at St David's in his day. Máedóc is mentioned in the Irish litany of pilgrim saints in the Book of Leinster – ‘the twelve pilgrims who went with Máedóc of Ferns across the sea’. He is commemorated in the Irish martyrologies on 31 January. It is claimed that Máedóc bequeathed his staff, bell, and reliquary, the famous Breac Máedóg, respectively to Ferns, Drumlane and Rossinver. The Breac Máedóg and the bell are preserved at the National Museum of Ireland and Armagh Public Library respectively, but the staff is not extant.