This obelisk is the twin of the one by the Palazzo Quirinale: they once stood outside the Mausoleum of Augustus. Their origin is unknown, but they may be of Roman manufacture, as they have no hieroglyphics. At some unknown date and by some unknown cause, the obelisks fell. In 1519 and in 1781 the two obelisks were discovered underground at the entrance of the Great Tomb of Emperor Augustus. This one was repaired and re-erected here in 1587, on the orders of Pope Sixtus V.