Alexander I of Yugoslavia reigned as the king of Yugoslavia from 1921 until his death in 1934. During a state visit to France, Alexander was murdered by Bulgarian Vlado Chernozemski. The assassination inspired the opening of Christopher Hyde's book, The Second Assassin. Alexander's life and career inspired a TV series titled Alexander of Yugoslavia.
Milan I of Serbia reigned as the King of Serbia from 1882 until his sudden abdication in 1889. He abdicated in favor of Alexander I of Serbia, which was unexpected at that time. During his reign, Milan focused on developing natural resources and improving the means of communication. However, he was largely unpopular due to reckless extravagance and heavy taxation.