AD 971:Battle of Dorostolon: A Byzantine expeditionary army (possibly 30–40,000 men) attacks the Bulgarian frontier, personally led by Emperor John I. He lays siege to the fortress city of Dorostolon (located on the Lower Danube), and is reinforced by a fleet of 300 ships equipped with Greek fire. The Kievan Rus' and their Bulgarian allies are reduced to extremities by famine. After a 3-month siege, Grand Prince Sviatoslav I agrees to sign a peace treaty with the Byzantines, whereby he renounces his interests towards Bulgarian lands and the city of Chersonesos in Crimea. Sviatoslav is allowed to evacuate his army to Berezan Island, while the Byzantines enter Dorostolon. John renames the city Theodoropolis (named after the reigning Empress Theodora).