Famuli vestrae pietatis
Famuli vestrae pietatis, also known by the Latin mnemonic duo sunt ('there are two'), is a letter written in 494 by Pope Gelasius I to Byzantine Emperor Anastasius I Dicorus on the relationship between religious and secular officials. == Description == Famuli vestrae pietatis is a letter written in 494 by Pope Gelasius I to Byzantine Emperor Anastasius I Dicorus which expressed the Gelasian doctrine.