Originally from, Edmund Sturge, a Quaker and advocate for abolition.The letter in Donald Mackenzie's book addressed Sturge's plea to the Sultan of Morocco to outlaw slavery in the region.
Engraving published as frontpiece of book "Trial and imprisonment of Jonathan Walker: at Pensacola, Florida, for aiding slaves to escape from bondage." Published Boston, at the Anti-Slavery Society Office, 25 Cornhill, 1848
This is a copy of the Treaty of Fez which was signed between France and the Moroccan sultan making Morocco a French protectorate. This started stricter views on slavery in Morocco.