At the center of the square stands an Egyptian obelisk of red granite, 25.5 metres tall, supported on bronze lions and surmounted by the Chigi arms in bronze, in all 41 metres to the cross on its top. The obelisk was originally erected at Heliopolis by an unknown pharaoh of the Fifth dynasty of Egypt (c. 2494 BC – 2345 BC). The Emperor Augustus (c. 63 BC – 14 AD) had the obelisk moved to the Julian Forum of Alexandria, where it stood until 37 AD, when Caligula ordered the forum demolished and the obelisk transferred to Rome. It was moved to its current site in 1586 by the engineer-architect Domenico Fontana under the direction of Pope Sixtus V.