When aged five his father died and his widowed mother, Jean Spottiswood, married James St. Clair of Rosslyn c.1667.
After four years he moved to Chartres and became a pensioner at St. Chéron's Abbey of Canons Regular and there completed his education in rhetoric.
At the abbey of Saint-Pierre de Rillé at Fourères, Brittany, he studied philosophy and divinity being ordained sub-deacon and deacon in September 1683.
Nonetheless, he found the opportunity to examine the documents held by the St. Clair family before being forced to return to France in June 1689.
His copies of these documents, which were written in English, Scots and Latin have been used extensively by historians since the loss of the originals.
The manuscripts, preserved in the National Library of Scotland, are the main source for the history of the Sinclairs and of Rosslyn Chapel.