An important source for jade is located in the north slopes of the Kunlun Mountains, near Khotan in the Tarim Basin. This region passed in and out of Chinese control over the centuries, until the eve of the thirteenth century CE, when the region reverted to local governance. A little more than a century later, Khotan was ruled by the Timurids, who, along with other Central Asian peoples, greatly valued jade. As noted by the British Museum, the tenth-century scholar al-Biruni noted that, in local language, the mineral was known as 'victory stone.' Timur (Tamerlane) was buried beneath a black jade cenotaph, and warriors and nobles decorated their swords, belts and saddles with jade. Ulugh Beg, Timur's grandson, was the owner of this cup.¹

The stone was not only admired for its beauty, but also for as its mystical potential to ward off evil, protect the bearer from physical harm, and even neutralize poison. Cups such as this example may have been made in order to exploit this last magical quality. The dragon handle was commonly used on Chinese drinking vessels created during the Song period (960-1279), and soon became popular in Central Asia and Persia, as did other Chinese-inspired design motifs.

References:

(1) From the British Museum web site dedicated to this object.

(2) Ibid.