The Sotheby family originally came from Yorkshire, England.
[1] Auction house Baker and Leigh was founded in London on 11 March 1744.
He was the nephew of Samuel Baker, who was the founder of the book auctioneering firm that later became Sotheby's.
After his uncle's death in 1778, John became a partner in his book auctioneering firm along with George Leigh.
He expanded the scope of the firm’s business to include the sale of prints, medals, coins, and rare antiquities.