John II Casimir (1609–1672) was the last of the Vasa dynasty to rule as elected King of Poland. He ascended the throne in 1649, after the death of his brother Ladislas, renouncing Holy Orders (he was a Jesuit who had been created Cardinal) and marrying his widowed sister-in-law, Mary of Gonzaga. After an astonishingly turbulent reign, during which he was several times driven into exile, he abdicated in 1668, one year after signing the Treaty of Androussovo with the Muscovites which led to a relentless increase in Russian interference in Polish affairs. After such a troubled reign it is a moot point as to what finally drove him to renounce the throne, but in fact it was probably the death of his wife in 1667. He settled in Paris, where he resumed his ecclesiastical career, accepting appointments as Abbot of Saint-Germain-des-Prés, and subsequently of Saint-Martin-de-Nevers.