The oldest established football club in Denmark is Kjøbenhavns Boldklub (KB), which was originally founded back in October 1876. While KB initially focused on other athletic pursuits like cricket, it pioneered association football in the country and later merged its professional football department in 1992 with Boldklubben 1903 to form the modern powerhouse F.C. Copenhagen, leaving a legacy as a foundational pillar of Danish football history.