Giovanni Battista Cairati, known in Portuguese service as João Baptista Cairato, was born at Cairate in Lombardy and learned his trade fortifying Malta and Sardinia for the Knights Hospitaller before directing the defence works of Milan through the 1560s. He entered the service of Philip II in 1577 and in 1583 was appointed chief engineer of the Estado da Índia, charged with rebuilding the Portuguese fortresses of the Indian Ocean to the angled-bastion geometry of the trace italienne. For a decade he worked between Vasai, Daman, Hormuz, Muscat, Mannar and Malacca. In about 1593 he chose the site and set out the plan of Fort Jesus at Mombasa, his last known work; he died at Goa in 1596, probably without seeing it finished, and was succeeded by Julio Simão.
