The term 1605 POPE OF is referring to Pope Paul V, who was elected in 1605 and served as pope until his death in 1621. He was a member of the Borghese family, and was known for his strong support of the Counter-Reformation and for his opposition to Galileo Galilei. The crossword solution for this term is FAWKES, which is likely a reference to Guy Fawkes, a member of the Gunpowder Plot who attempted to assassinate King James I in 1605.