in Rogo?no" by Wojciech Gerson.]]The broad definition of regicide is the deliberate killing of a monarch, or the person responsible for it. In a narrower sense, in the British tradition, it refers to the judicial execution of a king after alleged due process of law.
The regicide of Mary Queen of Scots
Before the Tudor period, English Kings were murdered while imprisoned (for example Edward II) or killed in battle by their subjects (for example Richard III), but none of these deaths are usually referred to as regicide. The word regicide seems to have come into popular use among foreign Catholics when Pope Sixtus V renewed the solemn bull of excommunication against the crowned regicide Queen Elizabeth I, for executing Mary Queen of Scots in 1587 among other things. She had originally been excommunicated (Regnans in Excelsis) by Pope Pius V for reverting England to Protestantism after the reign of Mary I of England (Bloody Mary). The defeat of the Spanish Armada and the "Protestant wind