(da Vignola), GIACOMO, an Italian architect, was born in 1507. While young he studied painting at Bologna, but, not succeeding, he turned his attention to perspective. At the same time he studied architecture, and visited Rome, where he measured nearly all the ancient edifices that still remained in that city. In his latter days he produced a valuable treatise on the five orders of architecture, which has become the alphabet of architects. He erected a magnificent palace at Minerbo, near Bologna, for the count Isolani; the house of Achille Bochi; the facade on the bank, and the canal of Navilio at Bologna. After the death of Michael Angelo, he was appointed architect of St. Peter's, and erected the two beautiful lateral cupolas.