This article focuses on two confessions of faith, which were composed in the late eleventh century by the philosopher John Italos and by the monk Nicetas Stethatos. In-depth analysis of selected passages shows that the two men subscribed to a Trinitarian theology that could be considered heretical. They denied the existence of a common divine substance that could safeguard the oneness of God and instead emphasised the closeness of the hypostases to each other, which made it impossible for them to accord to the hypostases the distinguishing function that the Cappadocians had given them. Thus it can be argued that it was their Tritheism that pushed them towards a ‘Sabellian’ solution.