Rho, Giacomo, brother of Giovanni, was born at Milan, Italy, in 1593. At the age of twenty he joined the order of St. Ignatius, and, after being ordained priest, he accompanied Nicolas Trigault to China. Being detained at Macao, he aided in defending the town against the Dutch, and in surrounding it with new fortifications (1622). He afterwards penetrated into the province of Shan-si, in 1624, where he preached in the native language with fluency. In 1631 he was ordered to Pekin, where he was employed, with P. Adam Schall, in drawing up the imperial calendar. Rho died in China, April 27, 1638. He left only one work, in Italian — an account of his voyage — entitled Lettere della sua Navigazione e delle Cose dell' Indie (Milan, 1620), but he is said to have composed many works in Chinese on religion, astronomy, and mathematics. See Kircher, China Illustrata.