Louis IV, also known as Louis the Pious or Louis the Debonair, was a prominent ruler of the Frankish Empire in the ninth century. Synonyms for Louis IV include King Louis, Emperor Louis, and Louis the Great. He is also sometimes referred to as Louis I of Aquitaine or Louis I of France. Louis IV was a notable leader who sought to expand the reach and power of the Frankish Empire, working to consolidate and strengthen his realm throughout his reign. His legacy as a successful monarch has endured throughout history, and his name remains synonymous with wise and just leadership.