When Constantine-Cyril was only 24 years old (851), the Byzantine rulers sent him on a mission to the Saracens in the region around Baghdad. The young philosopher and theologian was entrusted with the task of defending the Christians living there against attacks from the Muslims.

In his Life, Clement of Ohrid recounts how the Saracens (Hagarenes) tested Constantine-Cyril’s knowledge in various fields, asking him difficult questions about the symbols of the Christian faith – the Cross, the Trinity and the icons. He succeeded in explaining their meaning and in demonstrating the far greater power of Jesus compared with Muhammad:

“Christ /…/ raises upwards that which is heavy and teaches people through faith and divine virtues. Being the Creator of all things, He created man between the angels and the animals, distinguishing him from the animals by speech and reason, and from the angels by anger and desires. And whichever side a person inclines towards, to that side he becomes joined: either to the higher beings or to the lower [the animals].”