Quaestio 136 in pseudo-Athanasius' corpus of Quaestiones ad Antiochum (CPG 2257, PG vol. 28, coll. 597-700) is a quite intriguing text, which does not seem to fit in the rest of the corpus, in terms of language and of content. The question asked is how to convince Pagans that there is only one God, who is the God of the Christians. The answer to this question combines a survey of supernatural events, which are supposed to demonstrate the existence of God, with the statement that the birth of Christ was already announced by some of the "Wises" amongst the Pagans (in the tradition of the "Theosophy"). Quaestio 136 was probably used to fabricate the Περὶ τοῦ ναοῦ attributed to Athanasius and edited by A. Delatte in 1923. In this paper I would like to determine the sources used in both parts of Quaestio 136, and to elucidate its context of composition. I would also like to face the question as whether Quaestio 136 belongs or not to the original collection of Quaestiones ad Antiochum and where it comes from.