A detailed chart of the island of Zanzibar, surrounding islands and roads, from the Freycinet family archive, a fair copy of an original manuscript map, probably prepared by the Depot de la Marine, and once the basis for Alexander Dalrymple's chart 'Plan of the Island of Zanzibar on the East Coast of Africa: From a French Manuscript', published on April 17th, 1784. The chart may have been prepared for Henri Freycinet, who served as governor of the, not-so- distant, Île Bourbon (Reunion Island) from 1821 to 1826.

Zanzibar had been of significant interest to the French from the earliest decades of the eighteenth century, as part of their local slave trading operation. French merchants from the Mascarene Islands, Ile de France, now Mauritius, Bourbon, and Reunion, "required a regular and growing supply of slave labor for the colonial plantation economy, based on coffee and sugar, which mushroomed on the twin islands" (Alpers).

The period between 1771 and 1784, when this chart was probably drawn, was dominated by "a new singleness of purpose by all concerned parties and by the beginnings of serious French activity north of Cape Delgado, which was the northern limit of Portuguese influence" (Alpers). Zanzibar soon became the focus of all coastal trade north of Cape Delgado, and the centre of the French slave trade.

After the restoration of the monarchy in 1814, Henri Freycinet embarked on a second career, as a colonial administrator: firstly of the Isle de Bourbon, now Reunion, from 1821 to 1827; then of French Guiana, from 1827 to 1829, during which he was promoted to Rear-Admiral, and Baron; and lastly of Martinique, from 1829 to 1830. He died in Rochefort, Charente-Maritime, in southwest France, in 1840.