Islamic art encompasses the visual arts produced from the 7th century onwards by people who lived within the territory that was inhabited by or ruled by culturally Islamic populations. It is thus a very difficult art to define because it covers many lands and various peoples over some 1,400 years; it is not art specifically of a religion, or of a time, or of a place, or of a single medium like painting. The huge field of Islamic architecture is the subject of a separate article, leaving fields as varied as calligraphy, painting, glass, pottery, and textiles, among others.