In 1586 Domenico Fontana erected the obelisk in the Square of St. Peter's. Wiki: "This feat of engineering took the concerted effort of 900 men, 75 horses and countless pulleys and meters of rope. He gives a detailed account of it in Della transportatione dell'obelisco Vaticano e delle fabriche di Sisto V (Rome, 1590) [1] [2]. The astronomer Ignazio Danti is known to have assisted Fontana in this work. Fontana also used his knowledge of statics, which aroused universal astonishment at the time, in the erection of three other ancient obelisks on the Piazza del Popolo, Piazza di S. Maria Maggiore, and Piazza di S. Giovanni in Laterano."
