Eric XIV of Sweden

Erik XIV or Eric XIV (13 December 1533 – 26 February 1577) became King of Sweden following the death of his father, Gustav I, on 29 September 1560. During his reign, Erik sought to centralize royal authority and expand Swedish influence in the Baltic region, incorporating Reval (now Tallinn) and northern Estonia into the realm in 1561 to lay the foundations of the Swedish Baltic Empire. To consolidate control, he enacted the Articles of Arboga (1561), which restricted the political power of his half-brothers. His ambitions to control Baltic trade routes also led Sweden into the Northern Seven Years' War (1563–1570) against Denmark–Norway and Lübeck.

While Erik was regarded as intelligent, artistically skilled, and a promoter of Renaissance court culture, early in his reign he showed signs of mental instability, a condition that eventually led to insanity. Some scholars claim that his illness began early during his reign, while others believe that it first manifested with the Sture murders. During a 1568 rebellion against him, Erik was incarcerated by his half-brother John III. He was formally deposed by the Riksdag on 26 January 1569.

Erik, having been imprisoned and deposed, was most likely murdered. An examination of his remains in 1958 confirmed that he probably died of arsenic poisoning.