John III of Sweden
Swedish king (1537-1592)
John III (Swedish: Johan III; 20 December 1537 – 17 November 1592) was King of Sweden from 1569 until his death. He ascended the Swedish throne after successfully rebelling against his older half-brother Erik XIV. He is mainly remembered for his attempts to close the gap between the newly established Lutheran Church of Sweden and the Catholic Church, as well as his conflict with and possible murder of his brother.
John was also, quite autonomously, the Duke of Finland from 1556 to 1563. In 1581, he assumed the title Grand Duke of Finland. His first wife was Catherine Jagiellon of the Polish–Lithuanian ruling family, and their son Sigismund eventually ascended both the Polish–Lithuanian and Swedish thrones. He ended the Northern Seven Years' War, but instead, Sweden was drawn into the 25 Years' War with Russia, where minor gains were eventually made. He worked for closer relations with Poland. John III was interested in religion and culture. During his reign, he countered the growing Lutheran tendencies of the Church of Sweden under the influence of Duke Charles, and worked for a reunion with the Catholic Church and the Pope in Rome.
John III was the son of King Gustav I of Sweden and his second wife Margaret Leijonhufvud.
The public source identifies “John III of Sweden” as swedish king (1537-1592). This brief keeps that definition visible, then builds a research path around John, Sweden and Swedish.
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The entry’s evidential value lies in the named roles, institutions and publications that can be tested against primary documentation. The source revision retrieved here is dated Sep 14, 2026. The linked authority identifier is Q52944. VIAF identifies the subject as 15663342. The Library of Congress control number is n86037801. 2 of 3 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 1537, 1592, 1569 and 1556.
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This entry incorporates text from “John III of Sweden” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.