Early life, family and rise to power , John Casimir was born in
Kraków on 22 March 1609, the son of
Sigismund III Vasa and
Constance of Austria. John Casimir, for most of his life, remained in the shadow of his older half-brother,
Władysław IV Vasa. He had few friends among the Polish nobility. Unfriendly, secretive, dividing his time between lavish partying and religious contemplation, and disliking politics, he did not have a strong power base nor influence at the Polish court, instead supporting unpopular Habsburg policies. He did, however, display talent as a military commander, showing his abilities in the
Smolensk War against
Muscovy (1633). Between 1632 and 1635, Władysław IV sought to improve his brother's influence by negotiating a marriage for John Casimir to
Christina of Sweden, then to an Italian princess, but to no avail. In 1637, John Casimir undertook a
diplomatic mission to
Vienna, which he abandoned to join the army of the
Holy Roman Empire and fight against the French. After his regiment was defeated in battle, he spent a year living lavishly at the Viennese court, where his strong anti-Cossack interests and political views were greatly shaped under the direct influence of the Austrian Emperor. , 18th century In 1636, he returned to the
Polish–Lithuanian Commonwealth and fell in love with one Baroness Guldentern, but his desire to marry her was thwarted by King Władysław. As an apology, Władysław attempted to make him the sovereign of the
Duchy of Courland, but this was vetoed by the Commonwealth parliament (
Sejm). John Casimir took offense to this slight by the parliament, and in 1638 left for the Kingdom of Spain to become
Viceroy of Portugal, but was captured by French agents and imprisoned by the order of
Cardinal Richelieu until 1640. He was then freed by a diplomatic mission of the appointed
Voivode of
Smolensk, Krzysztof Gosiewski and as a result of
anti-French Polish-Spanish negotiations. In 1641, John Casimir decided to become a
Jesuit, leaving the Polish–Lithuanian Commonwealth to accompany his sister to
Germany. In 1643, he joined the Jesuits, despite vocal opposition from King Władysław, causing a diplomatic rift between the Commonwealth and
the Pope. John Casimir went to Rome upon an invitation from the Jesuits in order to bolster the Catholic faction. He was appointed cardinal, but he would soon resign and return to the Commonwealth when the only son of Władysław died. He attempted to gain the support of the
Habsburgs and marry an Austrian princess to create an alliance between the nations in case of an unexpected attack from the east.
King of Poland in 1648 In 1648, John Casimir was elected by the Polish Parliament to succeed his half-brother on the Polish throne. A year later, John II Casimir married his brother's widow,
Marie Louise Gonzaga (), who would prove to be a major support to the King. The reign of the last of the Vasas in the Polish–Lithuanian Commonwealth would be dominated by the
Russo-Polish War (1654–67), followed by the war with Sweden ("
The Deluge"), the scene for which had been set by the Commonwealth's two previous Vasa kings. Most of Poland was invaded by the Swedish army during The Deluge without much of a fight, due to the complicity of the Polish and Lithuanian governors and nobility. In the course of a few years, the Commonwealth rose to force the Swedes out of Poland, ending the short-lived intrusions and campaigns, however, at a high cost. Most of the cities and towns in the Commonwealth were sacked, plundered and some were burnt to the ground, mostly by the retreating enemy units. Although the reign of John II Casimir is remembered as one of the most disastrous and perhaps most unsuccessful in the history of Poland and the Polish-Lithuanian Commonwealth, he is often referred to as the "warrior king" who fought bravely to save his nation and his people. In 1660, John II Casimir was forced to renounce his claim to the Swedish throne and acknowledge Swedish sovereignty over
Livonia and the city of
Riga in modern-day
Latvia.
Abdication and death On 16 September 1668, grief-stricken after the death of his wife in the previous year, John II Casimir abdicated the throne of the Polish-Lithuanian Commonwealth and returned to France, where he rejoined the Jesuits and became abbot of
Abbey of Saint-Germain-des-Prés in Paris. Following his abdication,
Michał Korybut Wiśniowiecki was elected the new king and was crowned on 29 September 1669. John Casimir allegedly re-married to
Claudine Françoise Mignot. In the autumn of 1672, John Casimir had intended to return to Poland, but fell ill before departing and was prevented from doing so. The seizure of
Kamieniec Podolski by the
Ottoman Empire distressed him, exacerbating his condition. He requested the assistance of
Pope Clement X to defend Poland against the Ottomans. He died on 16 December 1672 from
apoplexy, and his burial took place inside the
Wawel Cathedral in
Kraków. His heart was interred in the
Abbey of Saint-Germain-des-Prés. == The Lwów Oath ==