What are the reasons for forming coalitions with respect to political and economic cooperations among countries? How do countries form coalitions? What are the preferences concerning potential partners and how are they shaped? Who wins and who loses in a coalition? Why are some coalitions terminated while others are not? International coalitions include long-term and complex relationships. The main goal of this study is to investigate the formation of coalitions with a focus on international agreements and the dynamics of Europes political economy. Within the presented research, several points will be considered such as the emergence and evolution of coalitions, heterogeneity among coalition members, and issues of potential enlargement.