sentences:  Abu'l-Khayr Khan was assisted in his consolidation by the Manghits, another tribe in the White Horde, and especially by Vaqqāṣ Bej, Edigü's grandson.In 1430–1431 Abu'l-Khayr, joined by Vaqqāṣ, launched on attack on Khwarezm, occupying the regional capital Urganj.The Uzbeks could not hold the city, however, and retreated in the summer of 1431.