The Count of Monte Christo mentions "aqua tofana".
Pope Clement XIV, who suppressed the Jesuit Order of Loyola, sickened and died rather suddenly.

11 All the world believed that Clement had been made to drink the Aqua Tofana, a spring in Perugia more famous than healthful. Some one has said that if Popes are not liable to err, they are nevertheless liable to sudden death.