Johan Jacob Ahrenberg, usually referred to as Jac (30 March 1847, in Vyborg – 10 October 1914, in Helsinki) was a Finnish architect, writer and artist.
Jac Ahrenberg studied architecture, inspired by his friend Theodor Höijer, for Fredrik Wilhelm Scholander at the Royal Institute of Art in Stockholm.
[2] Early in his career he became involved in the preparations of Finland's contributions to the world fair in Paris in 1878 and another exposition in Copenhagen in 1888, together with Robert Runeberg and Julius af Lindfors.
The couple had two sons and three daughters, Carl Gaston, Helge Edmund René, Signe Blanche Maria (Tandefelt), Märta Matilda Beatrice (Hertz) and Helga Cecilia Geneviéve (Franck).
[3] For the expositions in 1878 and 1888, Ahrenberg designed furniture and textiles and worked in a style that adhered to a pronounced European tradition but with details that were considered markedly Finnish.
He also published his memoirs in six volumes, Människor jag känt, in which he relates lively anecdotes about many well-known people of his time whom he knew personally, e.g. Heinrich Schliemann, Vasily Vereshchagin, Ivan Turgenev, Viktor Rydberg, Charles Garnier and Arthur de Gobineau; the racist ideas of the latter influenced Ahrenberg to a certain degree.