The European Court of Justice (ECJ) was founded in 1952. At that time, few observers would have predicted a future of a powerful institution, shaping Europe’s faith through its rulings. But that is exactly what happened. After a slow start, the ECJ gradually evolved into one of the most important institutions of the European Union. This chapter describes how this little court shrouded in secrecy managed to climb the institutional ladder. It analyses the role of institutional leadership, the relation between the ECJ and its authorizing environment, the near-existential crisis it faced in the 1970s, and the potential vulnerabilities that have grown over the years.