Significantly large numbers of Mozarabs settled in the Ebro valley. King Alfonso VI of Castile induced Mozarab settlers by promising them lands and rewards. His importation of Mozarab settlers from Al-Andalus was very unusual because of its startling nature. According to the Anglo-Norman historian, Orderic Vitalis, some 10,000 Mozarabs were sent by Alfonso for settlement on the Ebro. Mozarabs were scarce in Tudela or Zaragossa, but were more common in a place such as Calahorra, conquered by the Kingdom of Navarre in 1045.