When William I gave the go-ahead for the building of the Alte Nationalgalerie in 1861, this at last provided an opportunity to develop the Museum Island, which at the time consisted only of Karl Friedrich Schinkel's Altes Museum and Friedrich August Stuler's Neues Museum, in the form once dreamed of by Frederick William IV The Romantic on the Prussian throne had intended to transform the Spree island beyond Schinkel's museum into a "haven of art" and prepared some designs for it himself. Here we also find a building in the form of a temple on a high plinth for the first time. Stuler was commissioned to design the new building, but he died unexpectedly in 1865, even before work had started. His successor was Johann Heinrich Strack, who completed the building and its artistic furnishings by 1876.But this was not the end of the building history of the Alte Nationalgalerie, which became a national monument because of its triumphal lines. Museum directors like Ludwig Justi and Eberhard Hanfstaengl, new ideas about museums, urgently needed space, war damage and rebuilding in the days of the GDR changed the interior of the building fundamentally. It has now been completely refurbished on the occasion of the 125th anniversary of the museum's opening.