Site of the imprisonment of the Vorotynskii princes [Kirillo-Belozerskii Monastery, Kirillov, Russian Empire], 1909. The Kirillo-Belozersky Monastery (in present-day Vologda Oblast, northern Russia), was founded by Cyril of Beloozero in 1397. During the reign of Ivan IV, better known as "The Terrible", the monastery was both a retreat and a prison, a convenient place for the czar to dump his opponents into exile. Russian chemist and photographer Sergey Prokudin-Gorsky (1863-1944) was a pioneer in colour photography which he used to document early 20th-century Russia and her empire, including the vanishing way of life of tribal peoples along the Silk Route in Central Asia. In a railway-carriage darkroom provided by Czar Nicholas II, Prokudin-Gorsky used the three-colour photography process to record traditional costumes and occupations, churches and mosques - many now Unesco World Heritage sites - as well as modernisation in agriculture, industry and transport.