Year 305 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Megellus and Augurinus (or, less frequently, year 449 Ab urbe condita). The denomination 305 BC for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
Antigonus I Monophthalmus sends his son Demetrius to conquer Rhodes, which has refused him armed support against Ptolemy. He shows ingenuity in devising new siege engines in his unsuccessful attempt to reduce the city. Among his creations are a battering ram 60 metres long and requiring 1,000 men to operate it and a wheeled siege tower named "Helepolis" (or "Taker of Cities") which stands 40 metres tall and 20 metres wide and weighs 180 tons. This siege of Rhodes earns Demetrius the title Poliorcetes ("the City Besieger").