The Magna Carta is one of the most important documents in England's history. The first Magna Carta was also important to Scotland. It was a legal charter drawn up by the subjects of King John outlining their rights. Why was it also important to Scotland?
Because England was Scotland's overlord the rights expressed in it would also apply to Scots.
It explicitly states that King John should "do right" by Alexander, King of Scots with respect to the disputed northern regions of England.
It was written by a Scot living in England.
It was used as a model for a Scottish Magna Carta that was introduced by Scots ten years later.