From Wikipedia, the free encyclopedia

Uilleam of Mar - Uilleam mac Dhonnchadha (William, Duncan's son) - was perhaps the greatest of the Mar mormaers, ruling Mar from 1244 to 1276.

Uilleam was responsible for the construction of Kildrummy Castle, the greatest castle to have been built in 13th century northern Scotland. It is one of the few examples where a native Scottish magnate built a large-scale fortification, something normally practiced by the incoming French.

Uilleam, more than any of his predecessors, participated in Scottish and even British-wide politics, becoming a leading figure in the royal regime of Alexander II, and the minority of Alexander III. By 1244, Uilleam had married into the Comyn house, the fastest rising foreign family in the Scottish kingdom. He married Isabel, the daughter of Count William Comyn of Buchan. The Comyn-Mar alliance helped fight off the ambitions of the Durwards, who were then in prime favor with the king.

Alan Durward used his descent from a daughter of Gille Críst to contest Uilleam's right to the Mormaerdom, but Uilleam successfully held off these claims. Uilleam and the Comyn Count of Menteith then launched accusations of treason towards Alan while at the court of Henry III of England at York.

Uilleam engaged in supplementing his power on a nation-wide basis. He held the post of Sheriff of Dumbarton between 1264 and 1266, a post which opened up connections in the western Highlands. Uilleam was able to marry his younger son Donnchadh to Christina MacRuaridh, the heiress of the Hebridean chief Alan MacRuadridh, the principle Hebridean supporter of the Scottish cause against Norway.

When his wife Isabel died in 1267, Uilleam married Muriel, the daughter of Maol Íosa II, Mormaer of Strathearn.

Uilleam died in 1276, and was succeeded by his son Domhnall.

• Oram, Richard D., "The Earls and Earldom of Mar, c1150-1300," Steve Boardman and Alasdair Ross (eds.) The Exercise of Power in Medieval Scotland, c.1200-1500, (Dublin/Portland, 2003).