Sir William Keith was a Scottish nobleman and military leader known for his role in the early 15th century. He served as the Earl of Mar and was a prominent figure during the Wars of Scottish Independence. His leadership and military skills were crucial in various battles against English forces. Keith was also a supporter of Robert the Bruce, the King of Scots, and played a significant part in the struggle for Scotland's independence. His contributions to the Scottish cause helped solidify his reputation as a key figure in Scotland's history during a tumultuous period.