During the reign of the Abbasid Caliph Harun al-Rashid in the 8th century, Baghdad had become an important cosmopolitan city. Merchants from Persia, China, India, Africa, and Europe were all found in Baghdad. During this time, many of the stories that were originally folk stories are thought to have been collected orally over many years and later compiled into a single book. The compiler and ninth-century translator into Arabic is reputedly the storyteller Abu Abd-Allah Muhammad el-Gahshigar. The frame story of Shahrzad seems to have been added in the 14th century.