by Iltutmish in Tarain. Relations with slaves According to Minhaj's Tabaqat-i-Nasiri (c.1260), Muhammad of Ghor enthusiastically used to purchase several slaves during his lifetime who later according to Minhaj became renowned for their calibre "throughout the world". Muhammad purchased a young Qabacha who was sold into slavery and was later bestowed with the domains of Kerman and Sanjar for his Iqṭāʿ by the Ghurid Sultan. He raised his slaves with affection and treated them as his sons and successors, after his despondency with his own Ghurid household in his later days. According to another contemporary account of Fakhr-i Mudabbir who wrote under the patronage of Qutb ud-Din Aibak also emphasized upon the importance of each of the Turkish slaves ("bandagan") to Muhammad. He further panegyrise Aibak for enduring the trust of his master. Muhammad's slaves played a key role in the expansion and consolidation of the Ghurid conquests in the Ganga-Jamuna doab when he was engaged in the affairs of Khurasan and amidst this also raised their own authority in the North India while still regarding Muhammad of Ghor as their supreme master until his assassination. Muhammad of Ghor, later also organized matrimonial alliances among the families of his slaves in accordance with the practise of endogamy. The notable among these alliances, were the marriages of the daughters of Taj al-Din Yildiz to Qutb ud-Din Aibak and Nasir ad-Din Qabacha. Further, two daughters of Aibak were married to Qabacha. This policy was continued by Aibak as well, who married his daughter to his slave Illtutmish. In popular traditions, when a courtier lamented that the Sultan (Muhammad of Ghor) had no male heirs, he retorted: Legacy During his joint reign with brother Ghiyath al-Din Ghori, the Ghurids emerged as one of the greatest power of the eastern Islamic world. The Ghurids reached pinnacle of their territorial expansion where they briefly ruled over a territory which spanned over 3000 km from east to west. Muhammad of Ghor's empire stretched from Nishapur (although for a short span) in eastern Iran to Benares and Bengal in present-day India and from the foothills of the Himalaya south to Sindh (Pakistan). The Catastrophe of Andkhud and the collapse of the Šansabānī dynasty within a decade of his assassination along with the rise of Changez Khan who carved out the largest contiguous empire in history made his short-lived successes in the Khurasan and Persia as less consequential