The Shahnameh says King Faridun gave Iran to his youngest son, and the two elder sons killed him and sent his head to their father

Ferdowsi's Shahnameh, finished in 1010, tells this as legend; the king Faridun goes back to the Avestan hero Thraetaona. In Warner's 1905 translation, Faridun, worn with age, divides the world among three sons. Salm gets the West, Tur the Turkman lands and China, and the youngest, Iraj, gets Iran and Arabia with the throne. Salm grows envious and draws Tur in. Iraj goes to his brothers and offers to give up the crown: "I do not want the royal crown or throne." Tur strikes him with a heavy golden seat, then stabs him with a dagger and cuts off his head. The brothers fill the head with musk and ambergris and send it to Faridun. The old king falls from his horse, weeps for days, and burns Iraj's house and gardens. Iraj's widow has a daughter, whom Faridun raises; her son Manuchihr is trained for war. Salm and Tur send envoys asking forgiveness. Faridun's answer threatens war, and the Aga Khan Museum's caption says their faces turned "blue as lapis lazuli." Manuchihr kills both brothers, Faridun crowns him and dies. The scene is painted in Shah Tahmasp's Shahnameh, made in Tabriz about 1522 to 1535.