Bruce and former Guardian John Comyn had been debating how Scotland should be ruled. They met in Greyfriar's Kirk in Dumfries on 10 February 1306 but it is not clear what actually happened.
The two nobles met as rivals and tensions would have been high.
There was some sort of disagreement and when Bruce left the Church, Comyn was already wounded.
Some reports say that Bruce’s companion, Kirkpatrick, went back in to make sure Comyn was dead.
Other reports say that it was Bruce himself who killed Comyn.
Bruce had killed someone in a holy place which meant he had committed sacrilege (a crime against the Church).
As a result, Bruce was excommunicated (expelled from the Christian Church by the Pope).
Bruce still had the support of Bishop Wishart of Glasgow. He forgave Bruce and helped him to organise his coronation.
Bruce was crowned King of Scotland on 25 March 1306.
The coronations took place at Scone, where the Scottish Kings were traditionally crowned.
There were only a few supporters present and the ceremony was led by the Countess of Buchan.
The ceremony took place without the Stone of Destiny and the Scottish Crown Jewels.
At first Bruce had little support. He suffered a number of set-backs in his first few months as King.
At Methven Wood in June 1306 – Bruce was defeated by an English force and suffered heavy losses.
At Dalry in July 1306 – Bruce’s remaining supporters were virtually wiped out by the Scottish noble, John MacDougall.
In the autumn of 1306 - his brother, Neil Bruce was be-headed. His wife, sisters and daughter were placed under house arrest. One sister and the Countess of Buchan were imprisoned in cages.
Bruce fled from the Scottish mainland. He probably stayed the winter on an island off the west coast.