The Rahat al-sudur wa-ayat al-surur or Rahat al-sudur (Persian: راحة الصدور), is a history of the Great Seljuq Empire, its breakup into minor beys and the subsequent Khwarazmian occupation, written by the Persian historian Muhammad bin Ali Rawandi and finished around 1204/1205. Rawandi was encouraged and supported in his endeavour by Shihab al-Din al-Kashani. Written in Persian and originally dedicated to Süleymanshah II, Rawandi re-dedicated his work to the Sultan of Rum, Kaykhusraw I. Source: Wikipedia (en)