He was crowned in the presence of at least three bishops and four earls with the coronation, which followed the murder of John Comyn, Bruce’s main rival to the throne, a formal and solemn affair.
The King was draped in “kingly robes and vestments” which had been hidden away by Robert Wishart, the Bishop of Glasgow, until “this longed for day”, according to Ronald McNair Scott in his book Robert the Bruce, King of Scotland.
“(They) were brought out by the old man and set upon King Robert, and a circlet of gold was placed upon his head while the great banner of the kings of Scotland with its lion and scarlet lillies, that had lain so long concealed, was planted behind his throne,” the author wrote.
The Bishops of Moray and St Andrews were also in attendance as well as the Earls of Atholl, Lennox, Menteith and Mar.
Absent, however, was the Earl of Fife, who held the hereditary right to crown the kings of Scotland.
Still a youth and held in England as a ward of court in 1306, he unable to attend the coronation and perform his hereditary duties.
But his sister, 19-year-old Isabella MacDuff, the Countess of Buchan, went against the will of her husband - a loyal supporter of Edward I and close kinsman of the murdered John Comyn - by taking up the hugely symbolic role during the coronation.
“To her the call of Scotland and her youthful hero-worship of Bruce proved greater than her wifely duty,” Scott wrote.
“Seizing her husband’s finest horses, she rode with the upmost speed to Scone to act on her brother’s behalf” he added.
Isabella arrived a day too late but but King Robert took part in a second coronation ceremony, 48 hours after the first,so that the ancient tradition may be preserved, Scott wrote.
He added: “The golden circlet was lifted once more and placed upon the brow of Robert Bruce, Earl of Carrick, Lord of Annandale, King of Scots.”
Following the coronation, Edward I sent soldiers into Scotland to hunt down the new king.
Robert I fled and, as the manhunt continued across Scotland, the King’s brother - Nigel de Brus - and other supporters were discovered.
They were taken to Berwick-Upon-Tweed where the men were judicially condemned, hanged, drawn and beheaded.
After Bruce’s defeat at the Battle of Methven in June, Isabella was captured with Edward I also sending her to the Borders town.
There, she was confined to a cage that was hung from a tower at Berwick Castle as a warning to others. She remained in the cage for four years, according to accounts.