Demetrius now undertook an expedition against Rhodes, which had refused its aid in the attack upon Ptolemy. It was from the memorable siege of Rhodes that Demetrius obtained his name of "Poliorcetes." After in vain attempting to take the town from the sea-side, by means of floating batteries, from which stones of enormous weight were hurled from engines with incredible force against the walls, he determined to alter his plan and invest it on the land-side. With the assistance of Epimachus, an Athenian engineer, he constructed a machine which, in anticipation of its effect, was called Helepolis, or "the city-taker." This was a square wooden tower, 150 feet high, and divided into nine stories, filled with armed men, who discharged missiles through apertures in the sides. When armed and prepared for attack, it required the strength of 2300 men to set this enormous machine in motion. But though it was assisted by the operation of two battering-rams, each 150 feet long and propelled by the labour of 1000 men, the Rhodians were so active in repairing the breaches made in their walls, that, after a year spent in the vain attempt to take the town, Demetrius was forced to retire and grant the Rhodians peace. In 301 B.C., the struggle between Antigonus and his rivals was brought to a close by the battle of Ipsus in Phrygia, in which Antigonus was killed, and his army completely defeated. He had attained the age of 81 at the time of his death. A third partition of the empire of Alexander was now made. Seleucus and Lysimachus shared between them the possessions of Antigonus. Lysimachus seems to have had the greater part of Asia Minor, whilst the whole country from the coast of Syria to the Euphrates, as well as a part of Phrygia and Cappadocia, fell to the share of Seleucus. The latter founded on the Orontes a new capital of his empire, which he named Antioch, after his father Antiochus, and which long continued to be one of the most important Greek cities in Asia. The fall of Antigonus secured Cassander in the possession of Greece. Demetrius was now a fugitive, but in the following year he was agreeably surprised by receiving an embassy from Seleucus, by which that monarch solicited his daughter Stratonice in marriage. Demetrius gladly granted the request, and found himself so much strengthened by this alliance, that in the spring of the year 296 he was in a condition to attack Athens, which he captured after a long siege, and drove out the bloodthirsty tyrant Lachares, who had been established there by Cassander.