The Count of Boulogne was a title held by the rulers of the historic region of Boulogne-sur-Mer in northern France. This title emerged in the early medieval period and was significant in the feudal system, where counts governed territories on behalf of the king. The Counts of Boulogne played a crucial role in local governance and military matters. One of the most notable figures was Eustace II of Boulogne, who became a prominent leader during the Norman Conquest of England. The title eventually became associated with the English crown, particularly through the marriage of the Norman rulers and the Plantagenet dynasty, influencing both French and English history.