More than twelve hundred years ago, the country we now call England was inhabited by small groups of Anglo-Saxons who lived in rural communities called tuns (a group of ten families).
The Anglo-Saxon word for chief was gerefa, which was later shortened to reeve (group of 100 families). During the next two centuries, a number of changes occurred in their system which led to a new unit of government, the shire (groups of hundreds banded together), which is now known in America as a county. So to distinguish the leader of a shire from the leader of a mere hundred, the more powerful official name became known as a shire-reeve.
The word shire-reeve eventually became the modern word for sheriff (the keeper, or chief, of the county).
In the year 871, under King Alfred the Great, the Sheriff was responsible for maintaining law and order within his own county.
In 1215, King John signed the Magna Carta. In the text of the Magna Carta it mentioned the role of the Sheriff nine times further establishing the importance of the office.
Over the next few centuries, the Sheriff remained the leading law enforcement officer for the county.
In 1941, Walter H.Anderson, a prominent attorney of the Idaho, California and Tennessee state Bar and supreme Court of the United States Bar, wrote A Treatise On The Law Of Sheriffs which has become the foremost legal authority on the subject of Sheriffs.
Anderson states that "the Sheriff's primary obligation is to represent the sovereignty, authority, and interests of the state in his respective jurisdiction", whereas the Police department represents the interests of the local jurisdiction. Originally the Sheriff was the King' s man, representing the interests and authority of the King in his Shire, often controlled by noblemen not always sympathetic or loyal to the King. In preserving the rights of the government, he (the Sheriff) represents the sovereignty of the state and has no superior in his county.
The modern Office of Sheriff carries with it all of the common law powers, duties and responsibilities to preserve the peace, enforce the laws and arrest and commit to jail felons and other infractors of the law. The Sheriff is the principle conservator of the peace within the county.