He was married two times - both a daughter of Qu Boya (麴伯雅) - ruler of Gaochang. When Xuanzang visited Kunduz, he also brought a letter from his brother-in-law and ruler of Gaochang Qu Wentai (麴文泰) to Tardu. Yabgu received him despite being in ill condition. It was Tardu to advise him to make a trip westward to Balkh (modern Afghanistan), to see the Buddhist sites and relics. Xuanzang also witnessed a palace scandal when Tardu's firstborn son Ishbara Tegin fallen in love with his new step-mother (also aunt) and poisoned Tardu in 630.[4]