5. Ivan the Terrible vs. Prince Kurbsky
Ivan IV of Russia’s paranoia turned on his childhood friend and advisor, Prince Andrei Kurbsky. Their bitter correspondence—full of accusations, betrayals, and philosophical debates—mirrored Russia’s descent into autocracy and bloodshed, leading to Kurbsky’s infamous defection. In 1564, fearing Ivan’s wrath, Kurbsky fled to Poland, where he was received by King Sigismund II Augustus. Ivan’s subsequent letters to Kurbsky were filled with rage and accusations, reflecting his deepening paranoia. (britannica.com)
