Despite having 22 member states in common, the European Union (EU) and the North Atlantic Treaty Organization (NATO) have been unable to fully cooperate since 2004. Chief among the causal factors for this divide is the persistent conflict between Turkey and Cyprus. NATO requires that every state it shares security information with be a member of its Partnership for Peace (PfP) program. Accession to the PfP program requires unanimous approval by all NATO states. Turkey has not recognized the Republic of Cyprus since 1963, however, and has blocked its accession to PfP. Cyprus joined the European Union in 2004. The EU has a regulation requiring all member states to be present at security-related meetings. Since Turkey, a NATO ally, does not recognize Cyprus, however, a "participation problem" has resulted. The EU and NATO have not been able to fully cooperate since Cyprus joined the EU. This research analyzes the historical roots of the 1974 conflict involving Cyprus, Greece, and Turkey, and the current factors that prolong the Cypriot-Turkish stalemate. The thesis argues that overcoming the conflict would be beneficial for the island and the region, and would allow full NATO-EU cooperation to resume. The introduction provides an overview of NATO-EU cooperation and the negative effects of the Cypriot-Turkish conflict. Chapter II will offer a historical account of the origins and development of the conflict. Chapter III will investigate the factors that appear to prolong the conflict, including the parties that appear to benefit from the immobility and how they have contributed to the course that the conflict resolution process has followed. Chapter IV will assess the importance of overcoming the obstacles presented in the previous chapter and review the advantages of quickly and justly resolving the conflict for moral, operational, and economic reasons. This would signify "thawing" the frozen conflict. Chapter V, the concluding chapter, will present an analysis of the conflict drawing from the evidence examined in Chapters III and IV, with findings about the validity of the initial hypothesis. The origins of the 1974 war between Turkey and Cyprus lie deep in the storied history of the eastern Mediterranean. Cyprus and its people can trace their lineage back through ages of adversity far into antiquity. Owing to its strategic location at the nexus of three continents, the United Kingdom's special envoy to Cyprus, Lord David Hannay, wrote that "the story of Cyprus, from classical times down to its independence in 1960, was one of domination by outside powers." According to Andrew Borowiec, "raids, conquests, and colonial domination in various forms have helped to form a highly insular and stubborn race, convinced of its importance and attraction to the world." Firmly entrenched in their respective beliefs regarding the island, each side of Cypriot-Turkish dispute possesses long memories. In many ways the dispute since 1974 is the continuation of a thousand years of turbulent relations. The long series of events leading to the 1974 conflict can be divided into three eras: ancient history, the Ottoman Empire, and the Cold War. This chapter will demonstrate that the roots of the Cypriot-Turkish conflict are much older than they may appear, and stem from historically complex and violent relations between these culturally and religiously diverse peoples. Comprehending the dynamic history of the region and the fundamental character of the island sets the stage and its actors by creating a framework for understanding the events leading to the 1974 invasion.