When Marie Sinclair was born in 1562, in Haddingtonshire, Scotland, her father, William Saint Clair, was 20 and her mother, Sibil Cockburn, was 18. She married David Makgill about 10 September 1583, in Haddingtonshire, Scotland. They were the parents of at least 6 sons and 1 daughter. She died on 6 February 1606, in Midlothian, Scotland, at the age of 44.