Jacob Schiff
Warburg purchased from Perry Belmont a lot that measured 100 feet along Fifth Avenue, but required Gilbert to cover only half of it with his house, permitting a side lawn fifty feet across on the avenue. When it was completed, Warburg's father-in-law Jacob Schiff feared that it was ostentatious and would incite envy and anti-semitism. The Warburgs specified that they were pleased with Harry Sinclair's house and would like something similar, with details likewise drawn from the Late Gothic Hôtel de Cluny, Paris.