The Holy Monastery of St. Catherine on Mount Sinai has been characterized by scholars as the most celebrated of the world's monasteries, while in the conscience of the Orthodox peoples it was and remains the most revered and longed-for focus of pilgrimage after the Holy Places. In the course of the Monastery's fifteen centuries of uninterrupted life, and despite the great difficulties faced in the midst of alien peoples, not only has St. Catherine's managed to maintain the Orthodox faith intact and provide the Church and the Ecumenical Patriarchate with pre-eminent figures of Asceticism, but it also secured special privileges from the Prophet Mohammed and, at a later date, from popes of Rome and leaders of both the East and West. The Monastery thus proved itself a great spiritual hearth of Hellenism, rendering the most distinguished service to monasticism, Orthodoxy, the Church and the Greek people. At the same time, the Monastery acquired international fame as a unique centre of Byzantine icon painting. Here the specialist may study the uninterrupted development of this art from the 6th century up till the present day. Furthermore, the Monastery also developed its own Sinaitic school of icon painting with its own stylistic techniques and 'Sinaitic' subject matter. Examples of this school's work are encountered not only in icons but also in illuminated manuscripts of the calligraphic and chrysographic workshop of the Monastery's world-famous Library. The Monastery of Sinai, moreover, surrounded as it is by the fortification walls built by its founder, the Emperor Justinian, and isolated in the inhospitable desert, was through the centuries a secure haven for invaluable works of art sent from all corners of the Earth as devout offerings of the faithful. Byzantine, Post-Byzantine and Modern Greek works representing all types of ecclesiastical art make up the artistic treasures of the Monastery.