釋氏要覽 2.105

2.105

律云。跋難陀比丘持大蓋行（似今涼傘也）諸居士遙見謂是官人。皆避道。及近元是比丘。乃譏謙之。佛乃制戒。不應持大蓋。若天雨即聽（字平聲即開許也）。

The Vinaya says: 'The monk Upananda held a large parasol while walking (similar to the modern sunshade). Laymen seeing him from afar thought he was an official and yielded the road. When he approached, he was originally a monk, and they ridiculed and reviled him.' The Buddha then established the rule that one should not hold a large parasol; if it rains, it is permitted (the character has an even tone, meaning an exemption is granted).