Johannes IV, Emperor of the Danes, King of Germany and Burgundy, Lord-Protector of Rome (1098 - 1140) was the last king of the Danish Empire that controlled central Europe during the Middle Ages, ruling as Emperor of the Danes from his coronation at the imperial capital at Askevik in 1121 until his assassination in 1140. During his reign, the empire began a decline due to unrest in Burgundy, which became the first kingdom to secede from the Danish realm in 1134 when Henry, Duke of Lyons crowned himself King of Burgundy. His assassination led to the crowning of Frederick II of the Danes, his younger brother, after which the Johannine Empire as it existed collapsed.