The question of Bruegel’s religion has long been the subject of discussion, and in order to answer it scholars have usually referred to single historical sources or works without taking the larger context into account. Additionally, often works or groups of works were taken as an argumentative basis of which the production contexts are only partially, if at all, documented. This article attempts for the first time to answer this open question by taking into account all known historical sources and those works of which historical contexts are known. The premise is the theory of the historian Reinhart Koselleck who introduced ‘the sources’ right of veto’: rather than define what can be claimed, historical sources reveal what should not be claimed. Based on this premise, Bruegel was a Catholic – just as his friend the geographer Abraham Ortelius – and he never gave his contemporaries reasons to doubt his religious denomination.