Mark Duncan was born in Roxburghshire, most probably in 1570, the son of Thomas Duncan of Maxpoffle, Roxburghshire and Janet Oliphant, daughter of Patrick Oliphant of Snowdoun, also in Roxburghshire. He died in Saumur. While little is known of Duncan's early life he is thought to have had his education partly in Scotland and partly on the Continent. Duncan certainly graduated MD but from which institution and in exactly which year are both uncertain. His subsequent successes as a practising mediciner were sufficiently significant to attract an offer of employment in that capacity at the English court from James I. Duncan is believed to have rejected King James's offer in virtue of his wife's unwillingness to quit France, her native land. Beyond the fact that Duncan's wife was ‘a French lady’, nothing now seems to be known of her. While Duncan was certainly a successful practising physician in France, his academic skills and achievements extended well beyond medicine to the extent that he is fairly described as a polymath.
From The Continuum Encyclopedia of British Philosophy in Oxford Reference.