In 1704, an Anglo-Dutch force captured Gibraltar in the name of Charles, Archduke of Austria who claimed the crown of Spain during the War of the Spanish Succession. The Lines were named after him. They saw use during the Twelfth Siege of Gibraltar (1704–5), when the Spanish and their French allies succeeded in breaching the defences but were repelled; during the Thirteenth Siege (1727), when they were bombarded by the Spanish; and during the Great Siege (1779–83), when they were again under Spanish bombardment. During the tenure of William Green as Gibraltar's Senior Engineer from 1761–83, the Lines were repaired, improved and fortified, and the cliffs below were scarped to make them impossible to climb. Facing west towards the Bay of Gibraltar, they were intended to make it possible to enfilade any attacking force trying to reach the gates of Gibraltar; they are connected to the Queen's Lines via a communication gallery completed on 13 September 1782.