The Habeas Corpus Act received royal assent on 27 May 1679. Habeas corpus already existed. The act made the remedy harder to ignore.

Habeas corpus was a way of testing detention. A prisoner could be brought before a court, and the court could ask by what authority that person was being held. Locking someone up was a direct use of power. If a person could be held and kept away from a court, the remedy meant less in practice.

The act dealt with that problem. It put tighter rules in place on delays and evasion, making it harder for officials to avoid court scrutiny or move prisoners out of reach. Its strength was procedure: bring the prisoner before the court and justify the detention.

The political setting gave the act its force. Late Stuart England was shaped by suspicion of arbitrary government, religious tension and arguments over royal authority. In that climate, detention without proper legal oversight was not a distant legal question. It was one of the ways authority could be used.

The act had limits. It did not fully establish modern civil liberties, and habeas corpus could still be suspended in later crises. Even so, the law mattered because it made imprisonment more answerable to the courts. A prisoner could not so easily be left hidden behind official delay.