A Frankish King was a ruler of the Franks, a group of Germanic tribes that played a significant role in the early medieval period in Europe. The most famous Frankish King was Charlemagne, who expanded the kingdom and became the first Holy Roman Emperor. Frankish Kings were known for their military prowess and efforts to unite various tribes under one rule. The Frankish Kingdom was established in the 5th century and became a powerful force in Western Europe. These kings often converted to Christianity, which helped to spread the religion throughout their territories. Their reigns laid the foundation for modern European nations.