Excerpt:
Ulugh Beg was the oldest son of Shahrukh, born in the city of Sultaniyah during his grandfather Timur's (Tamerlane's) campaign in northern Iran in 1394. At age 4 he accompanied his grandfather as far as Kabul, on the campaign that went on to take Delhi; almost immediately after the Indian campaign, he joined Tamerlane's campaign to the west which resulted in the defeat of the Ottoman ruler Bayezid I at Ankara in 1402. As Tamerlane was preparing to invade China, he celebrated the marriages of several of his grandsons, among them Ulughbeg (then age 10), who also was designated to rule over a significant portion of Moghulistan (the region encompassing part of the Tien Shan Mountains and NW Xinjiang), which, of course, was yet to be conquered. It is likely that Ulugh Beg was one of the princes seen by the Spanish ambassador Clavijo when he visited Tamerlane's court in 1403-1404.