O nullum crimen, nulla poena sine lege à luz do artigo 7.º da Convenção Europeia dos Direitos do Homem*

The principle that only the law can define a crime and prescribe a penalty is a modern civilizational achievement of different societies affiliated with the legal culture of civil law. However, its real meaning and effective scope are put to the test in the field of International Criminal Law, which is heavily influenced by common law traditions. This article seeks to analyze the case law of the European Court of Human Rights (ECHR) on this matter. The aim is to highlight not only points of approximation or convergence with the most current approach to that guarantee within the framework of continental law, but also points of distancing or fragility, especially oscillations regarding the requirements of the “quality of law”.