The name Charles is theorised to be derived either from the Germanic name Karl, which means "man" or the common Germanic name element hari, meaning "warrior, army". The name was originally popularised on continental Europe by Charles the Great, more commonly known as Charlemagne, an early ruler of much of Europe. It did not become common in Britain until the 17th century when King Charles I came to power. Although its popularity has begun to wane, it was an extremely popular choice when it was at its peak in the 19th and 20th centuries.