Charles was the third and posthumous son of Louis the Stammerer by his second wife, Adelaide of Paris. As a child, Charles was not allowed to become king in 884 when his half-brother Carloman died. The Frankish nobles instead asked his cousin, Charles the Fat, to rule over them. King Charles the Fat was not a good king so he was removed (deposed) in November 887. He died soon after in January 888. The nobility elected Odo, the hero of the Siege of Paris as their king. Charles Simplex was put under the protection of Ranulf II of Aquitaine who used the royal title himself until making peace with Odo.