Shams al-Din likely came from one of the eminent families of Sistan.Bosworth, p. 429 In mid-1236 he was hailed as malik by the people of Sistan, a year after the Mongols had captured the capital city of Shahr-i Sistan. After rebuilding fortresses that had been destroyed by the Mongols and establishing his authority over the outer towns of the province, he left his brother Mubaraz al-Din Abu'l-Fath in charge of Sistan and traveled to the ordo of Ögedei Khan. There Shams al-Din was confirmed as the khan's vassal; he was obliged to pay Mongol taxes and to destroy a stronghold in the district of Farah.
