Did You Know? Some monarchs reign for a very long time. Where they can ascend to the throne as children (as in ancient Egypt), they can reign even longer. The longest-reigning king in world history is often thought to be the Egyptian Pharaoh Pepi II, who many Egyptologists believe reigned for 94 years (!). He reigned c. 2278-2184 B.C. Since so much depended on the pharaoh, it is thought that his very advanced age toward the end may have contributed to the decline of the Old Kingdom and the chaos that followed. Still, if he lived to his late 90s, at one time he must have been mighty peppy. LEARN MORE.