glorious imperial reign
Archaic honorific term for the reign of an emperor, used in classical or historical contexts. Not used in everyday modern Japanese.
In old documents, the emperor's reign is praised with the word '大御代'.
Compound of 大 (おお, 'great') + 御代 (みよ, 'imperial reign'). The exact historical derivation is uncertain, but it follows a pattern of honorific prefixation in classical Japanese.