A conspiracy to coordinate a Spanish invasion of England with a rising of English Catholics, to assassinate Elizabeth I, and to replace her on the throne with Mary, Queen of Scots. Anthony Babington (1561–86) was the go-between in the secret preparations. Walsingham monitored Babington’s correspondence with the captive Queen Mary until he had enough evidence of her treasonable intentions to have her tried and executed in 1587, Babington having been executed at Tyburn after torture.