(*) Al-Khidr is named after the Arabic word for this color, which was replaced in many places with red in the Ottoman Empire as part of the process of secularization.
The southeast corner of the Masjid an-Nabawi features a dome of this color resting over a tomb. In Islamic legend, a figure traditionally depicted wearing robes of this color guides Alexander the Great to the Fountain of Youth. Only sayyids were allowed to wear turbans of this color in the Ottoman Empire. A mysterious servant of God who is shown wearing this color kills an innocent boy and repairs the decrepit wall of a village while acting as a guide for Moses. (*) Al-Khidr is named after the Arabic word for this color, which was replaced in many places with red in the Ottoman Empire as part of the process of secularization. This was the favorite color of Muhammad and consequently his early followers used it as their flag. For 10 points, name this color of the banners of the Rashidun Caliphate, as well as its admirers like Saudi Arabia and Libya.
The southeast corner of the Masjid an-Nabawi features a dome of this color resting over a tomb.
green [accept al-Khidr until it is read]