The Battle of Valdejunquera took place in a valley called Iuncaria between the Islamic emirate of Córdoba and the Christian armies of the kingdoms of León and Navarre. The battle, a victory for the Córdobans, was part of the "campaign of Muez" (campaña de Muez), which was directed primarily against León's southern line of defence, the county of Castile along the Duero river. The Leonese king encountered the Muslims—whom we know from other sources to have been under the command of their emir, ‘Abdarrahmān III—in the Valdejunquera and was routed.