His largest commission was the Nordic Museum on Djurgården, in North European Renaissance style, which he began in collaboration with M. Isaeus but continued alone after Isaeus's death in 1890.
At the turn of the century the ironworks business went well, and the Manor was once more overhauled, this time by Isak Gustaf Clason.
N.20, Brandstodsbolagets hus ("House of the Fire-insurance Company"), designed by Isak Gustaf Clason (1856–1930) and built by the turn of the century 1900 in the style of Tessin the Younger.
Carl XVI Gustaf of Sweden | Carl Gustaf Emil Mannerheim | Gustaf VI Adolf of Sweden | Gustaf Bonde | Gustaf V of Sweden | Gustaf Tenggren | Gustaf Fröding | Erik Gustaf Geijer | Carl-Gustaf Rossby | Isak Gustaf Clason | Gustaf Nordenskiöld | Gustaf Mauritz Armfelt | Gustaf Dalén | Gustaf Cederström | Carl Gustaf von Rosen | Carl Gustaf af Leopold | Johan Gustaf Renat | Isak N Jiyeon | Ísak Guttormsson | Gustaf Wally | Gustaf von Paykull | Gustaf Skarsgård | Gustaf Retzius | Gustaf Philip Creutz | Gustaf Murray | Gustaf Molander | ''Gustaf Mauritz Armfelt'' standing next to the bust of Alexander I of Russia | Gustaf Komppa | Gustaf Kjellvander | Gustaf Johan Billberg |