The first known publishing of the quote “Patiences is a virtue" comes from the poem “Piers Plowman” written between the years 1360 and 1387. Typical of texts from the 14th century, authorship can be debated though literary historians normally attribute most of the text to William Langland. However, there are multiple versions of this poem written at different times with sections believed to be authored by different, unknown people.
“Piers Plowman” is a poem about a man, the poet and first narrator, in search of Catholicism and faith according to medieval standards. He does this by having dream visions after falling asleep.
The various characters include Truth (God), Wrong (Devil), Holy Church, Thought, Wit, Study, Conscience, Liar, Reason, Dowel (do well), Dobet (do better) and Dobest (do best) and others, including the seven deadly sins.
Later, the characters are lead on a quest by Piers Plowman who also becomes the narrator. The Plowman is chosen as the guide due to his seemingly innocent and truthful nature.
It is also important to note that Latin and French versions of this quote also appear during that time. This means that this idea belongs to more than one religion and culture.
Common sentiments such as this often make their way into literature of the time, which makes it difficult to pinpoint the exact origin of the text since the quote would have been well known to people through an oral story tradition since many people were not literate.