The Sources of Celsus's Criticism of Jesus

This book is about what Celsus wrote about Jesus in the Second Century, what Celsus's image of God was like, and especially where Celsus found the ammunition to criticize Jesus so fiercely. Why did Christianity's growth bother a pagan philosopher, who was committed to Roman religion? Why did it bother a Platonic philosopher, although Christianity was never meant to be a philosophy? Egge Tijsseling...