1902 King Abdulaziz recaptured Riyadh , to become the first cornerstone in founding the Kingdom of Saudi Arabia. Following this, surrounding city residents, including al-Kharj , al-Hariq, al-Hawtah, Wadi ad-Dawasir , and al-Aflaj, pledged allegiance to King Abdulaziz. 1904 King Abdulaziz annexed the cities of al-Mahmal, al-Shuaib, Shaqra , Tharmada, and al-Washm. Then, he expanded further until the entire Sudayr region became under his control. 1904 King Abdulaziz annexed the city of Unayzah ...