John III of Sweden

John III was crowned King of Sweden after deposing his half-brother Eric XIV. His reign focused on religious reconciliation and cultural patronage, including the introduction of the Red Book liturgy.

John III ordered the continued imprisonment of his deposed half-brother Eric XIV, who was held at various castles until his death in 1577. This secured John's throne but created a lasting stain on his reign.

John III continued Sweden's involvement in the Livonian War against Russia, seeking control over Estonia and Livonia. The war ended inconclusively in 1583 with the Treaty of Plussa, ceding some territories to Sweden.

John III invited Jesuit priests to Sweden to promote Catholic-Lutheran dialogue and secretly negotiated with the Papacy about a possible reunion. The mission failed due to Protestant opposition and the Jesuits' expulsion in 1580.

John III issued the Red Book (Liturgy of 1576), a new church liturgy that incorporated Catholic elements into Lutheran worship. This attempt to reconcile Catholicism and Lutheranism caused conflict with the Swedish clergy and nobility.