Hugh IV of Boulogne was a nobleman who lived during the 12th century. He was the son of Hugh III of Boulogne and became the Count of Boulogne after his father's death. His reign was marked by the political complexities of feudal Europe, where alliances and conflicts were common. Hugh IV was known for his involvement in the Crusades, a series of religious wars aimed at reclaiming the Holy Land. He played a role in the governance of his territory and was part of the broader network of European nobility during a time of significant change and turmoil.