Habeas corpus is sometimes called "The Great Writ". It is a legal instrument first guaranteed following the signing of the Magna Carta. Its literal meaning is "show the body". Its purpose is to prevent the state from holding prisoners in extrajudicial detention. A writ of habeas corpus essentially challenges the legality of the detention. When a writ of habeas corpus is filed with a court in countries which inherit elements of their judicial system from the English system of Justice the state has to show that there is a legal basis for the captive's detention—usually that they are suspected of having broken a law. The principle of habeas corpus is codified in many humanitarian law treaties and national legislation – the right of fair trial and detainment is considered a basic human right.