3.1 million enslaved people trafficked to the British colonies

John Mason was captain-owner of three slaving voyages from London between 1795 and 1799: a man or men of the same name was captain of a slaving voyage from London by the Iris in 1785 and captain-owner of a further slaving voyage by the Henry in 1786. The 1800 will (made in 1789) for John Mason, master mariner of Rotherhithe about to set off for coast of Africa included as one of his trustees James Ogle (q.v.).