Revisiting the writings of the Socinian tradition and of the most eminent Christian orientalists, La Croze, in Réflexions historiques et critiques sur le Mahométisme, et sur le Socinianisme, once again proposes the parallel between the Mohammedan creed and the Socinian creed, as already noted by Hottinger in the second edition of Historia Orientalis. The sect of modern Socinians shares with the Mohammedan religion the same syncretic vision and admits a wide tolerance towards non-fundamental articles of faith. In this framework, the theme of antitrinitarianism is woven as the fulcrum of each comparison between Socinianism and Mohammedan religion and one of the affinities of the latter with the unitaires. This study aims to analyze this parallelism, reproposed in Bernard Cérémonies et coutumes religieuses de tous les peuples du monde, which – especially in the second half of the Seventeenth century and well beyond the early Eighteenth century – was used to argue on the one hand a heterodox position, tolerant and deist, and on the other to strengthen the apologetics in defence of Christianity.