大比丘三千威儀 2.103

2.103

Formerly, when the Buddha was in the world, the assembly's clothing was purely uniform and did not wear mixed secular attire. Later arose the bhikṣu Raśmisena (?), who, whenever he went for piṇḍapāta, always returned hungry and empty-handed. The Buddha, knowing his past sins and wishing to show retribution and merit to display a clear precept for future generations, divided the saṅgha into five schools to wear kāṣāyas of five colors, and thereupon they handed down this system one after another. Straight down until after the Buddha passed away, titles and names were established, adopting long-standing names and the colors of their robes.