John I of France

John I, called the Posthumous, was king of France and Navarre, as the posthumous son and successor of Louis X, for the five days he lived in 1316. He is the youngest person to be king of France, the only one to have borne that title from birth, and the only one to hold the title for his entire life. His reign is the shortest of any French king. Although considered a king today, his status was not recognized until chroniclers and historians in later centuries began numbering John II, thereby acknowledging John I's brief reign.