 Complete the following phrase:  In January 1902, Emir Abdulaziz ibn Saud Al Saud, who was at the time living in exile in Kuwait, returned to Riyadh and led an ambush against the Masmak fortress, regaining it from the House of Rasheed in the Battle of Riyadh. The event, which restored Saudi control over Riyadh, is considered one of the most important in the completion of the 