Penitenziagite ("Do penance") is a rallying cry derived from the Latin "Poenitentiam agite," meaning the same.
It has been also interpreted as a paraphrase of the Greek "πένητες διάγετε" attributed to Christ ("penites diagete"), meaning "live life as a pauper".
The phrase was used by the Dulcinian movement founded by Gerard Segarelli (1240–1300) in the 13th century, a movement named after the disciple Fra Dolcino.
It is also used by Guillermo del Toro as Pappy McPoyle in season 8, episode 3 of It's Always Sunny in Philadelphia, "The Maureen Ponderosa Wedding Massacre".
A sample of Ron Perlman's character from the 1986 movie The Name of the Rose saying the word appears in the song "Endemoniada", the first track on the album The Nephilim, by the band Fields of the Nephilim.