Complex sentence: He was a Commissioner for the Treaty of Peace with Anna of Oldenburg, signed at Aberdeen 19 October 1556 confirmed by Mary, Queen of Scots, 26 September 1557, and attended at the coronation of King James VI of Scotland in 1567.
Split into simpler sentences: He was a Commissioner for the Treaty of Peace with Anna of Oldenburg, signed at Aberdeen 19 October 1556 confirmed by Mary, Queen of Scots, 26 September 1557. He attended at the coronation of King James VI of Scotland in 1567.