Augustine of Hippo wrote two books about lying: On Lying (De Mendacio) and Against Lying (Contra Mendacio). He describes each book in his later work, Retractions. Based on the location of De Mendacio in Retractions, it appears to have been written about 395 AD. The first work, On Lying, begins: "Magna quæstio est de Mendacio" ("There is a great question about Lying"). From his text, it can be derived that St. Augustine divided lies into eight categories, listed in order of descending severity:
- Lies in religious teaching
- Lies that harm others and help no one
- Lies that harm others and help someone
- Lies told for the pleasure of lying
- Lies told to "please others in smooth discourse"
- Lies that harm no one and that help someone materially
- Lies that harm no one and that help someone spiritually
- Lies that harm no one and that protect someone from "bodily defilement"
Augustine wrote that lies told in jest, or by someone who believes or opines the lie to be true are not, in fact, lies.