Clan Donnachaidh the Battle of Methven in 1306. The clan asserts that Stout Duncan's relatives and followers (not yet known as Robertsons) supported Robert the Bruce at the Battle of Bannockburn in 1314. His descendants became known (in English or Scots) as the Duncansons, or Gaelic "Clann Dhònnchaidh", "Children of Duncan". Duncan is believed to have been killed at the Battle of Neville's Cross and was succeeded by Robert, from who the Clan Robertson takes its name. Robert's brother, Patrick, was the ancestor of the Robertsons of Lude who were the principal cadet branch. In 1394 a clan battle took place between
Richard Óg de Burgh, 2nd Earl of Ulster of King Robert the Bruce of Scotland. However, this did not stop him leading his forces from Ireland to support England's King Edward I in his Scottish campaigns and when the forces of Edward Bruce invaded Ulster in 1315, the Earl led a force against him, but was beaten at Connor in Antrim. The invasion of Bruce and the uprising of Felim Ó Conchúir in Connacht left him virtually without authority in his lands, but Ó Conchúir was killed in 1316 at the Second Battle of Athenry, and he was able to recover Ulster after the defeat of Bruce at