The article presents the influence of Greek philosophy on early Christian thought. This was done on the example of the influence of Middle Platonism on the views of Tatian Syrian and Athenagoras of Athens. I focus on their understanding of cosmological issues related to questions about the cause, nature and purpose of the world. Firstly, I reconstructed the cosmological thought of Tatian and Athenagoras because their preserved writings do not directly address these issues; next, I compared previous findings with the cosmological views of the 2nd century Platonists (Alcinous, Plutarch, Apuleius) to observe similarities and differences. Their different understanding of God’s goodness determined their understanding of causes, nature and the purpose of the cosmos. Other cosmological conclusions seem to emerge from this, which highlights the specificity of Christian and Platonic thought of the 2nd century. In addition, in the writings of the Greek Apologists we can find a new approach to matter which is not viewed as the second, eternal cause of the world.