Earl (/ /,) is a rank of the nobility in the United Kingdom. The title originates in the Old English word eorl, meaning "a man of noble birth or rank". The word is cognate with the Scandinavian form jarl, and meant "chieftain", particularly a chieftain set to rule a territory in a king's stead. In Scandinavia, it became obsolete in the Middle Ages and was replaced by duke (hertig/hertug/hertog). After the Norman Conquest, it became the equivalent of the continental count (in England in the earlier period, it was more akin to a duke; in Scotland, it assimilated the concept of mormaer). However, earlier in Scandinavia, jarl could also mean a sovereign prince. For example, the rulers of several of the petty kingdoms of Norway had the title of jarl and in many cases they had no less power than their neighbours who had the title of king. Alternative names for the rank equivalent to "earl" or "count" in the nobility structure are used in other countries, such as the hakushaku (伯爵) of the post-restoration Japanese Imperial era.