Aso O. Tavitian, the late software entrepreneur and philanthropist, was the kind of collector you rarely encounter anymore: self-made but low-profile, and with an omnivorous appetite for aristocratic treasures. The sales of his collection, taking place at Sotheby’s this week, contain more than 800 lots—and that’s just the Georgian mahogany furniture, pietra dura tables, Persian rugs, French silk panels, Baroque bronzes, gilt mirrors, Chinese export porcelain, silver, and some 40 paintings that he did not donate to the Clark Art Institute in the Berkshires. As dealer Harry Apter wrote in the sale’s catalog, Tavitian was a collector on par with Andrew Mellon, Henry Clay Frick, and J.P. Morgan.