William of Mar, also known by the name Uilleam mac Dhonnchaidh (

Anglicized Anglicisation or anglicization is a form of cultural assimilation whereby something non-English becomes assimilated into or influenced by the culture of England. It can be sociocultural, in which a non-English place adopts the English language ...

as "William, Duncan's son"), was the

mormaer of Mar There are currently two earldoms of Mar in the Peerage of Scotland, and the title has been created seven times. The first creation of the earldom is currently held by Margaret of Mar, 31st Countess of Mar, who is also clan chief of Clan Mar. Th ...

in medieval

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

from 1244 to 1276. His father was Donnchadh of Mar. Uilleam was responsible for the construction of

Kildrummy Castle Kildrummy Castle is a ruined castle near Kildrummy, in Aberdeenshire, Scotland. Though ruined, it is one of the most extensive castles dating from the 13th century to survive in eastern Scotland, and was the seat of the Earls of Mar. It is owne ...

, 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 A fortification (also called a fort, fortress, fastness, or stronghold) is a military construction designed for the defense of territories in warfare, and is used to establish rule in a region during peacetime. The term is derived from Lati ...

, something normally practiced by the incoming

Normans The Normans (Norman language, Norman: ''Normaunds''; ; ) were a population arising in the medieval Duchy of Normandy from the intermingling between Norsemen, Norse Viking settlers and locals of West Francia. The Norse settlements in West Franc ...

. 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 Scoto-Norman family in the Scottish kingdom. He married Elisabeth Comyn, the daughter of William Comyn, jure uxoris Earl of Buchan and Marjory, Countess 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 Alan Hostarius (or Alan Durward) () (died after 1264, or in 1275) was the son of Thomas de Lundin, a grandson of Gille Críst, Mormaer of Mar. His mother's name is unknown, but she was almost certainly a daughter of Máel Coluim, Mormaer of ...

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 Earl of Menteith then launched accusations of treason towards Alan while at the court of

Henry III of England Henry III (1 October 1207 – 16 November 1272), also known as Henry of Winchester, was King of England, Lord of Ireland, and Duke of Aquitaine from 1216 until his death in 1272. The son of John, King of England, King John and Isabella of Ang ...

York York is a cathedral city in North Yorkshire, England, with Roman Britain, Roman origins, sited at the confluence of the rivers River Ouse, Yorkshire, Ouse and River Foss, Foss. It has many historic buildings and other structures, such as a Yor ...

. Uilleam engaged in supplementing his power on a nationwide 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 Cairistíona Nic Ruaidhrí, daughter of the Hebridean chief

Ailéan mac Ruaidhrí Ailéan mac Ruaidhrí (died ×1296) was a leading figure in the thirteenth-century kingdoms of the Isles and the Scotland. He was a son of Ruaidhrí mac Raghnaill, and thus a member of the Clann Ruaidhrí branch of Clann Somhairle. Ailéan ...

, a man who had been one of the principal supporters of the Norwegian cause against the Scottish Crown in the 1260s. When his wife Isabel (also called Elizabeth) died in 1267, Uilleam married Muriel, the daughter of Maol Íosa II,

Mormaer of Strathearn Earl or Mormaer of Strathearn is a title of Scottish nobility, referring to the region of Strathearn in southern Perthshire. Of unknown origin, the mormaers are attested for the first time in a document perhaps dating to 1115. The first known mo ...

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

Domhnall Donald is a Scottish masculine given name. It is derived from the Gaelic name ''Dòmhnall''.. This comes from the Proto-Celtic Proto-Celtic, or Common Celtic, is the hypothetical ancestral proto-language of all known Celtic languages, and a ...

Bibliography

* 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). 1276 deaths Nobility from Aberdeenshire 13th-century mormaers Lord high chamberlains of Scotland Year of birth unknown Mormaers of Mar {{scotland-bio-stub