[1] Born in Montrose, he was the son of merchant William Clerk (d.1620), and was baptised by Alexander Forbes, the Bishop of Caithness, at Fettercairn on 22 December 1611.
[3][4] Clerk bought paintings in Paris, some from the collections of Cardinal Richelieu, and sold them to William Kerr, 3rd Earl of Lothian.
[5] Making international transfers of money for clients by bills of exchange depended on a network of merchant contacts, including John Jousie and Robert Inglis based in London.
He paid Thomas Cosh to fetch and feed doves from nearby landowners, from Clerk's small dovecot in the gable end of the stable, and from the nesting holes built in the main house.
[12] Clerk attended the weddings of his servants at the kirk of Penicuik, and recorded expenses he paid towards the food and entertainment "at the brydell" for himself and other members of the family and household.
[16] By this marriage the Clerk family inherited the "Penicuik Jewels" which are thought to have belonged to Geillis Mowbray, a companion of Mary, Queen of Scots.