The agreement proposed that if Scotland was conquered by England, the lands north of the Scottish sea (the Firth of Forth) would be divided between the Lord of the Isles and the Earl of Douglas to be held from the crown of England, while the Earl of Douglas would hold Scotland south of the Firth.
This agreement was made in anticipation of a potential English conquest of Scotland. It outlined how the land north of the Firth of Forth would be divided amongst the Lord of the Isles and the Earl of Douglas if England took control of Scotland. The Earl of Douglas would then hold the southern part of Scotland.