Claim: Shirt of Flame(Tunica molesta) refers to a specific form of the poison dress trope in folklore or type of clothing which were  doused with tar, pitch and oil, and set alight and used on Christians and martyrs in the Roman Empire.
Evidence: The phrase Shirt of Flame refers either to a specific form of the poison dress trope in folklore, or to a particular type of clothing given to people about to face burning at the stake. During the Persecution of Christians in the Roman Empire, many early Christians were executed by being doused with tar, pitch and oil, and set alight in Rome. As such, they martyrs wore the metaphorical "Shirt of Flame" as they were consumed. Often they were stripped and forced to wear a Tunica molesta or "annoying shirt" that was impregnated with oil, that was also a "Shirt of Flame". A tunica molesta (Latin for "annoying shirt") was a shirt impregnated with flammable substances such as naphtha or resin, used to execute people by burning in ancient Rome.