The COVID-19 crisis has had, and continues to have, enormous effects on the European economy. To restore the latter's transmission mechanisms and mitigate the financial impact, the European Central Bank (ECB) introduced its Pandemic Emergency Purchase Programme (PEPP), a €750 million purchasing plan. This article discusses the legality of this programme, using the European legal framework and the recent framework generated by the German Constitutional Court (GCC). This article claims that the PEPP is legal under the European framework. By contrast, the PEPP would not be considered legal by the German Constitutional Court, though this may change owing to recent developments. This article furthermore analyses the impact of this programme upon the mandate of the ECB. It describes the changes in the role of the ECB in recent years, from a cautious bank to a bank ready to fight a crisis. This extension has generated tensions between the core and periphery countries, resulting from underlying flaws in the European Monetary Union (EMU) which can only be solved by further integration or disintegration.