The Habeas Corpus Act 1679 is an Act of the Parliament of England (31 Cha. 2 c. 2) passed during the reign of King Charles II by what became known as the Habeas Corpus Parliament to define and strengthen the ancient prerogative writ of habeas corpus, a procedural device to force the courts to examine the lawfulness of a prisoner's detention in order to safeguard individual liberty and thus to prevent unlawful or arbitrary imprisonment.