During the time of the Byzantine Empire, embroidery developed a great deal, thanks to contact with the orient and the introduction of silk. Artists often copied from Persian models and enhanced their work with pearls and with gold and silver threads. In the Byzantine Empire and other Orthodox lands (Bulgaria, Serbia, Imperial Russia, etc.), fine needlework studios developed, which produced exquisite banners, some of which today are displayed in museums around the world. Spain and Italy were equally influenced by Byzantine tastes, and by the Middle Ages, the use of richly embroidered church banners is attested in both the East and the West.