King Alexander III dies when he fell off his horse at Kinghorn in Fife in March 1286. Which lead Scotland having a succession crisis, as there was no heir to the throne.
The guardians Margaret ( Alexander's granddaughter), the Maid of Norway, who was 3 years old would be queen. A Regent would be appointed to rule until Margaret is old enough to rule on her own. The King of Norway is persuaded to allow his daughter to come to Scotland.
Edward I was interested in becoming involved with Scotland's affairs and suggested to the guardians that Margaret can be married to his son. But Margaret died of seasick on the way to Scotland.
Without a strong leader, Scotland would be in danger of attack from other countries. The guardians call for help from Edward I.
Some of the powerful Scottish noblemen thought they had the right to be king of Scotland. Whoever wanted to be the king had to accept Edward as their overlord. There were 14 applicants for becoming the king.
The apllicants were narrowed down to Robert the Bruce and John Balliol. In November 1292, Edward I decided that John Balliol had the strongest claim to the throne of Scotland.