Mary Queen of Scots gave explicit approval for the assassination of Elizabeth I through her letter to Anthony Babington on 17 July 1586.
Mary's coded letter to Babington authorized the assassination of Elizabeth and a coordinated armed uprising, providing the evidence Walsingham needed to destroy her.
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Tom Holland: And that's the significance of that otherwise kind of enigmatic phrase, 'Then shall it be time to set the six gentlemen to work.' In other words, get the assassination squad out there. Let them kill Elizabeth.