The successful conduct of an indigo factory, as he states in his own account, enabled him to retire from business after about ten years and settle in London.

The 1855 work was reissued ten years later in a much more extended form in three volumes, under the title of A History of Architecture in all Countries from the Earliest Times to the Present Day.

[2] In 1849 Fergusson published a metaphysical study, Historical Inquiry into the True Principles of Beauty in Art: More Especially with Reference to Architecture.

In 1859, he was the only civilian appointed to the Royal Commission on the Defence of the United Kingdom,[3] which subsequently recommended a huge programme of coastal fortifications that became known as "Palmerston's Follies".

[1] Although not a prolific practising architect, a small number of examples of Fergusson's architecture remain in existence, the most notable of which are the parliament building of Jamaica,[citation needed] and the Marianne North Gallery in Kew Gardens.