What is Mere Christianity? Mere Christianity is Christianity at its most basic, and therefore unifying form. Most well-read Christians will know the term from the famous author C. S. Lewis. However the idea of clarifying Christianity’s core predates Lewis’ landmark radio talks and subsequent book by a large margin. The early church wrestled with this as the faith was under siege by any number of heresies and heterodoxies. What is Christianity? Their answer was to formulate creeds. The first and most widely known of these we call the Apostle’s Creed, though none of the original apostles were involved in its writing. I believe in God, the Father almighty, creator of heaven and earth. I believe in Jesus Christ, his only Son, our Lord, who was conceived by the Holy Spirit, born of the Virgin Mary, suffered under Pontius Pilate, was crucified, died, and was buried; he descended to the dead. On the third day he rose again; he ascended into heaven, he is seated at t