Three types of theology developed in the ante-Nicene Church: the Asia Minor school, best represented by Irenæus (_v._ § 33); the North African, represented by Tertullian and Cyprian (_v._ § 39); and the Alexandrian, in the Catechetical School of which Clement and Origen were the most distinguished members. In the Alexandrian theology the tradition of the apologists (_v._ § 32) that Christianity was a revealed philosophy was continued, especially by Clement. Origen, following the bent of his genius, developed other sides of Christian thought as well, bringing it all into a more systematic form than had ever before been attempted. The Catechetical School of Alexandria was the most celebrated of all the educational institutions of Christian antiquity. It aimed to give a general secular and religious training. It appears to have been in existence well before the end of the second century, having been founded, it is thought, by Pantænus. Clement assisted in the instruction from 190, and from about 200 was head of the school for a few years. In 202 or 203 he was forced by persecution under Septimius Severus to flee from the city. He died before 215. Of his works, the most important is his three-part treatise composed of his _Protrepticus_, an apologetic work addressed to the Greeks; his _Pædegogus_, a treatise on Christian morality; and his _Stromata_, or miscellanies. Origen became head of the Catechetical School in 203, when but eighteen years old, and remained in that position until 232, when, having been irregularly ordained priest outside his own diocese and being suspected of heresy, he was deposed. But he removed to Cæsarea in Palestine, where he continued his work with the greatest success and was held in the highest honor by the Church in Palestine and parts other than Egypt. He died 254 or 255 at Tyre, having previously suffered severely in the Decian persecution. His works are of the highest importance in various fields of theology. _De Principiis_ is the first attempt to present in connected form the whole range of Christian theology. His commentaries cover nearly the entire Bible. His _Contra Celsum_ is the greatest of all early apologies. The _Hexapla_ was the most elaborate piece of text-criticism of antiquity. Additional source material: Eusebius. _Hist. Ec._, VI, deals at length with Origen; Gregory Thaumaturgus, _Panegyric on Origen_, in ANF. VI. (_a_) Clement of Alexandria, _Stromata_, I, 5. (MSG, 8:717.) Clement’s view of the relation of Greek philosophy to Christian revelation is almost identical with that of the apologists, as are also many of his fundamental concepts.