One of the earliest uses of ‘number' in theology concerned the very possibility of counting hypostases as a mark of their spatio-temporal distinctness. However, the council of Chalcedon allowed the use of number for counting two natures, divine and human in one single hypostasis of Christ. This statement and its implications raised severe opposition from many Christians and it comes as no surprise that it echoed two centuries later in the dispute between the Monothelites and the Dyothelites. St Maximus the Confessor took position against the former's interpretation of number as producing separation and opposition in Christ and the aim of this paper is to present the structure of his arguments as based mainly on Epistles 13-16. I hold that Maximus' central thesis that number does not bring any relation (i.e. separation, union etc) between beings is based on two key philosophical assumptions of the theologian of Christ's two wills and energies: one, coming from ontology, which proposes in a very Aristotelian manner that all activity refers either to substance or accident and hence number cannot actually introduce by itself a relation. The second originates in some of Maximus' logical considerations regarding the interpretation of difference as a relation between different relata. I will end with some brief remarks on the modern view of number which I take to be relational in exactly the sense criticized by Maximus.