Short answers, pulled from the story.
The Kingdom of Khotan was conquered in 1006 by Yusuf Kadir Khan, the Muslim Kara-Khanid ruler of Kashgar. This ended Khotan's existence as an independent Buddhist state after more than a thousand years.
The Kingdom of Khotan was located on the southern branch of the Silk Road, along the southern edge of the Taklamakan Desert in the Tarim Basin, in what is now Xinjiang, China. Its ancient capital was at Yotkan, west of modern-day Hotan.
The people of Khotan spoke Khotanese, an Eastern Iranian language of the Saka branch, and Gandhari Prakrit, an Indo-Aryan language related to Sanskrit. By the 10th century, Khotanese was an officially recognized court language used in royal administrative documents.
According to the account of the Chinese pilgrim Xuanzang, a Chinese princess smuggled silkworm eggs and mulberry seeds into Khotan by concealing them in her headdress. Xuanzang placed the event in the first quarter of the 5th century. From Khotan, silk production techniques eventually spread to India and later to Europe.
Khotan was famous for nephrite jade, silk, carpets, fine felts, and pottery. Jade from Khotan had been exported to China since at least the Shang dynasty, with pieces found in Chinese tombs dated as far back as 1200 BC. Silk bolts also served as currency for purchasing goods including camels, horses, and foodstuffs.
The Book of Zambasta is the most famous surviving Buddhist manuscript from Khotan. It is an original literary work written in Old Khotanese, an anthology exploring different themes of Buddhism, and is named after the official Ysamasta who commissioned it. Unlike most other Khotanese Buddhist texts, it was not a translation from Sanskrit.