In 1650, Leith was a prospective battleground when the Army of the Covenant, led by General David Leslie, threw up an earthen rampart between Calton Hill and Leith to defend the northern approach to Edinburgh against Oliver Cromwell's forces. This rampart became the line of one of Edinburgh's longest streets, Leith Walk. After Cromwell's victory at the Battle of Dunbar in 1650 and subsequent occupation of Scotland, a fort known as "Leith Citadel" was erected in 1656 to regulate the port traffic. All that remains of the fort today is a vaulted trance in Dock Street which was its main entrance.