This article studies the development of antisemitism in Austria in the late nineteenth century through the example of Josef Deckert. The priest is depicted in historiography as one of the most prominent anti-Jewish agitators of that period, but his path to antisemitism has not been explored. This research indicates that Deckert's adoption of antisemitic ideology happened abruptly and was not guided by ecclesiastical or lay authorities. The article, therefore, invites us to look more at individual actors and local cultures and less on strategies from above when studying the spread of populist movements. At the same time, the analysis draws attention to two aspects that have been studied little in connection to the diffusion of antisemitism in the modern period, the cult of Saint Joseph and the remembrance of the Turkish siege of Vienna. Deckert was deeply devoted to Saint Joseph and invoked the patron saint of the Habsburg monarchy, not only as protector of Catholic Austria at the time of the Ottoman wars, but as patron of the workers and defender against the contemporary Austrian Jews.