Clan Sweeney supporters of the powerful MacDougall Lords of Lorne who supported John Balliol as patriots, as long as John was king of Scotland. After the murder of John Comyn, the nephew of Balliol, by Bruce in 1306, the First War of Scottish Independence became at one and the same time a civil war. The Balliol and Comyn parties taking the side of the English in opposition to Bruce, crowned Robert I of Scotland on 25 March 1306. This was an era of constantly shifting alliances, and in 1301 John MacSween was in alliance with Aonghus Óg Mac Domhnaill, Lord of Islay
Elizabeth de Burgh Carrick, at the English court, and they married in 1302 at Writtle, near Chelmsford, Essex, England. Elizabeth would have been about 18 years old, and Robert 28. On 27 March 1306, Robert and Elizabeth were crowned as King and Queen of Scots at Scone. The coronation took place in defiance of the English claims of suzerainty over Scotland after the execution of Sir William Wallace. After his coronation, she is quoted as having said, as though anticipating a defeat by Edward I. After the defeat of the Scots at the Battle of Methven on 19 June 1306, the king sent