Mathu, one of three gods, the others being Nuada and Goibhniu, who appear as three heathen prophets in an early account of St. Patrick. There is also Mathgen, a druid of the Tuatha Dé Danann in “The Second Battle of Mag Tuired.”

Matholwch

[W] King of Ireland who marries Branwen, daughter of Llyr. He is slighted by her half-brother Efnisien and in revenge mistreats Branwen, forcing her to do menial tasks in his kitchens despite the birth of their son Gwern. This leads to an invasion of Ireland by Bran, Branwen’s brother, and a destructive battle in which Matholwch is killed. Only five pregnant women are left alive in all Ireland to repopulate the country.

Mathonwy

[W] Ancestor of the house of Don. His children were Don, the mother-goddess, and Math, god of increasing wealth.

Matrona

Divine Mother, a Gaulish goddess. See Mabon.

Meargach

[I] “Of the Green Spears.” Husband of Áille who is killed by Oscar.

Mechi

[I] Son of the Mórrígán, goddess of death and battles, who is slain by Mac Cécht, son of Ogma, because it is prophesied that he will bring disaster to Ireland. He had three hearts in which grew three serpents that, when full grown, would break out and devastate the land.

Medb

[I] Sometimes Anglicised as Maeve. It has been argued that she was another triune goddess representing sovranty. She is most famous for her appearance in the epic of the Táin Bó Cuailgne.

Meddygon Meddfai

[W] Three sons of a mortal and an Otherworld spirit who, through her knowledge, became the greatest physicians in Wales. See Llyn y Fan.

Medicine

Much is made of the skills of ancient Celtic physicians, especially the Irish. During the Dark Ages (the Golden Age of Learning for Ireland) the Irish medical schools were famous throughout Europe. The premier medical school of Europe was at Tuaim Brecain (Tomregan, Co. Cavan) in the fifth century a.d. Both the Brehon Laws and the Laws of Hywel Dda are very explicit on medical practices. The oldest surviving medical books in Irish date from the early fourteenth century and constitute the largest collection of medical manuscript literature, prior to 1800, surviving in any one language.