Originally, the arhats composed of only 10 disciples of Gautama Buddha, although the earliest Indian sutras indicate that only 4 of them, Pindola, Kundadhana, Panthaka and Nakula, were instructed to await the coming of Maitreya. Earliest Chinese representations of the arhats can be traced back to as early as the fourth century,and mainly focused on Pindola who was popularized in art by the book Method for Inviting Pindola.
Later this number increased to 16 to include patriarchs and other spiritual adepts. Teachings about the Arhats eventually made their way to China where they were called Luohan, but it wasn't until 654 AD when the Nandimitr?vad?na, Record on the Duration of the Law, spoken by the Great arhat Nadimitra, was translated by Xuanzang into Chinese that the names of these arhats were known. For some reason Kundadhana was dropped from this list.
Somewhere between the late Tang Dynasty and early Five Dynasties and Ten Kingdoms period of China two other Luohans were added to the roster increasing the number to 18. But this depiction of having 18 Luohans only gained a foothold in China whereas other areas like Japan continue to revere only sixteen and whose roster differs somewhat. This depiction of having 18 instead of 16 Luohans continues into modern Chinese Buddhist traditions. A cult built around the Luohans as guardians of Buddhist faith gained momentum amongst Chinese Buddhists at the end of the ninth century for they had just been through a period a great persecution under the reign of Emperor Tang Wuzong. In fact the last two additions to this roster, Taming Dragon and Taming Tiger, are thinly veiled swipes against Taoism.
