 This spectacular feat of arms took a mere twenty-one years, no mean task considering the distances and terrain involved, and the fact that mechanical transport on land was not then in use.The strategic importance of Gibraltar rose in the last years of the Moorish rule, when, after the successful Spanish reconquest of the entire Guadalquivir valley, Gibraltar became one of the key elements in communication between the Kingdom of Granada and Moorish domains in northwestern Africa.Construction of the Moorish Castle commenced in the 8th century AD (possibly AD 711); the date of its completion is not recorded.