Rū'īn Dez, sometimes also called just Rū'īn, was a fortress near Maragheh in Iran that served as the main dynastic stronghold and residence of the Ahmadili Atabegs of Maragheh in the 1100s and early 1200s.[1] Vladimir Minorsky tentatively located it at present-day Yayshahr, 16 km north of Maragheh on the slopes of Mount Sahand.[2]: 262 In 1174/5 (570 AH), the Eldiguzid ruler Muhammad Jahan Pahlavan besieged Ru'in Dez and then Maragheh, each time unsuccessfully.[1] In 1197, when the poet Nizami Ganjavi completed his Haft Peykar, he sent it to his patron, the Ahmadili atabeg Ala ad-Din, who received it at Ru'in Dez.[1] After Ala ad-Din died in 1207 or 1208 (604 AH) and then his young son died a year later, the Eldiguzid atabeg Abu Bakr invaded Ahmadili territory.[1] A eunuch who stayed loyal to the Ahmadili family took up a defensive position at Ru'in Dez with Sulafa Khatun, Ala ad-Din's granddaughter, along with the dynastic treasury.[1] Ru'in Dez was the only Ahmadili possession that did not come under Abu Bakr's control.[1] Sulafa Khatun remained in charge at Ru'in Dez after the Mongols took Maragheh itself in 1220 or 1221 (617 AH).[1] Her reign came to an end after a siege of Ru'in Dez by the Khwarazmshah vizier Sharaf al-Molk when Jalal al-Din Mangburni arrived, made her marry him, and installed a new governor at Ru'in Dez.[1]