This book solves the long-standing mystery of a Christian monastery near Samarkand, seen and described by two Arab travellers in the tenth century. Despite several attempts made since the 1890s, its precise location had never been established. The first part covers the quest, the find, and the archaeological excavations’ results. Then the author proceeds to search for a mediaeval Christian enclave near modern Tashkent, which appears to have been washed away by a river that changed its course over centuries. Apart from the Christians, the book also touches upon the Manichaeans, Buddhists, Zoroastrians and other Sogdians, their languages, faiths, and material remnants.