Count, and the female equivalent, countess, is a European title of nobility whose authority is below that of a marquis or duke and above that of a viscount. Counts were originally military commanders in charge of a fixed locality, and the title was not necessarily hereditary. The word "count" comes from the Latin "comes," a title meaning (imperial) "companion" that denoted high-ranking officials who served the Roman Emperor.
The tile and role of count evolved from that of the "comes," important military or administrative helpers of the Emperor during the late Roman Empire. After the fall of Rome, the Germanic kings appointed counts to lead countships, which consisted of a military force in a set locality, as opposed to a mobile warband. Counts had nearly equal power with Catholic bishops, and the two often had adversarial relationships. Although counts were normally subordinate to dukes, some countships, like those of Flanders and Barcelona, were as large as duchies.
Gradually, the countship evolved into a hereditary title. After the Middle Ages, feudalism ceased to be the dominant socioeconomic structure of Europe. Kings reasserted their power, and the vassals, including counts, lost their political authority, although they retained privileges of nobility and limited influence at the royal court.
The British equivalent of a count is an earl.