[1] He was at one point a loyal supporter of King James III and served as an ambassador to England in the 1470s and 1480s.
During his service, Lord Lyle negotiated various treaties with England, including a three-year truce.
[2] In 1482,[1] after a series of disagreements, Robert was accused of plotting high treason against the King, James III.
[3] In 1485, after James III repeatedly enraged the nobles, Robert Lord Lyle joined several other peers in a confederacy to depose the king.
[6] Lyle's Duchal Castle was eventually besieged for a week, with the famous cannon Mons Meg part of the King's armament.