About the transportation of the Vatican obelisk by Domenico Fontana
Ever since the 1530s, Fabbrica di San Pietro architects had been mulling over the possibility of moving the large obelisk on the south side of the Basilica to Piazza San Pietro. At one stage or another, Antonio da Sangallo, Camillo Agrippa and even Michelangelo were involved in the project. It was only after Sixtus V’s election to the Papal throne that, between April and September 1586, thanks to the Pope’s insistence and Domenico Fontana’s ingenuity, the project was swiftly implemented. Drawing on Imperial Roman techniques, Fontana took down, moved and re-erected the obelisk in the centre of the square using a complex system of levers and winches, plus a large number of skilled workers (blacksmiths, masons and carpenters). Fontana meticulous described the entire operation in his book Della trasportatione dell’obelisco Vaticano e delle fabriche di nostro signore papa Sisto V, which was published in Rome in 1590 with illustrations by Natale Bonifacio. A century later, with financial support from the Fabbrica di San Pietro, Innocent XI commissioned Carlo Fontana to write a major monograph on the Vatican Basilica, in which he reconstructed the various stages of how the obelisk had been moved in words and pictures (engraved by Alessandro Specchi).
Domenico Fontana, Della trasportatione dell'obelisco vaticano et delle fabriche di nostro signore papa Sisto V fatte dal cavallier Domenico Fontana architetta di sua santità..., Roma 1590 [ma 1604]