[4] In 1640, the Dutch built the first simple fort in the form of stone nog and brick lodge under the direction of Commander, Arent Jacobsz van der Graeff.

In 1698, the Royal African Company "licensed" ship captains not in its employment upon the payment of a 10% "affiliation fee" to enable them to trade in its areas of monopoly.

Anomabu became a popular haunt of "ten percenters" (until their licensing was stopped in 1712), exporting vast numbers of slaves.

In 1717, the Dutch director-general at Elmina, Engelgraaf Roberts, quoting an English captain on Anomabu slave trade exports, stated: "From January 1702 to August 1708 they took to Barbados and Jamaica [from Anomabu] a total of not less than 30,141 slaves and in this figure are not included transactions made for other ships sailing to such Islands as Nevis, Montserrat, St. Christopher, for the South Sea Company, the New Netherlands and others which would increase the above number considerably, and of which Annemaboe alone could provide about one third.

[8] In the nineteenth century, its commander Brodie Cruickshank added one storey to the main building, and renamed the fort after King William IV (1830 – 1837).