The attempt to install Lady Jane Grey as Queen of England collapses after only nine days.

Lady Jane Grey, also known as Lady Jane Dudley after her marriage, and nicknamed as the "Nine Days Queen", was an English noblewoman who was proclaimed Queen of England and Ireland on 10 July 1553 and reigned until she was deposed by the Privy Council of England, which proclaimed her cousin, Mary I, as the new Queen on 19 July 1553. Jane was later beheaded for high treason.

A queen regnant is a female monarch, equivalent in rank, title and position to a king. She reigns suo jure over a realm known as a kingdom; as opposed to a queen consort, who is married to a reigning king; or a queen regent, who is the guardian of a child monarch and rules pro tempore in the child's stead or instead of her husband who is absent from the realm, be it de jure in sharing power or de facto in ruling alone. A queen regnant is sometimes called a woman king. A princess, duchess, or grand duchess regnant is a female monarch who reigns suo jure over a principality or (grand) duchy; an empress regnant is a female monarch who reigns suo jure over an empire.