Islamic influences on Western art refers to the influence of Islamic art, the artistic production in the Islamic world from the 8th to the 19th century, on Christian art. During this period, the frontier between Christendom and the Islamic world varied a lot resulting in some cases in exchanges of populations and of corresponding art practices and techniques. Furthermore, the two civilizations had regular relationships through diplomacy and trade that facilitated cultural exchanges. Islamic art covers a wide variety of media including calligraphy, illustrated manuscripts, textiles, ceramics, metalwork and glass, and refers to the art of Muslim countries in the Near East, Islamic Spain, and Northern Africa, though by no means always Muslim artists or craftsmen. Glass production, for example