Impartial and independent courts are cornerstones of the success of the European project. The recent renaissance of ‘illiberal states’, to use the words of Viktor Orbán in 2014, jeopardizes the application of the rule of law and risk destroying the foundations of the EU legal order. During 2018, the ECJ has developed two new lines of case law: On the one hand, the ECJ has made itself competent to rule on matters regarding the independence of the judiciary, which used to be part of the pure internal competence of the Member States. On the other hand, the ECJ has empowered national courts to realize a ‘rule of law’ check of other Member States, by assessing the independence and impartiality of the issuing judicial authorities in the context of the arrest warrant – a new task for courts of first instance. This project aims at analyzing this recent evolution using a European, historical and procedural perspective. It aims to build bridges between parts of the legal science – EU law, legal history and procedural law – which seldom interact. Combining the methods of EU law, with a certain focus on the case-law of the ECJ, the methods of procedural law based on understandings of a ‘fair trial’, and the historical methods, which shed light on how independence and impartiality of judges developed, this will be a fruitful way of getting a better understanding of the strengths and weaknesses in the protection of the independence and impartiality of the judiciary.