(2) Catechetical Schools. This type of school also originated at Alexandria, and arose out of the intellectual activities which made that city so important a centre during the first and second centuries of the Christian era. Pantaenus, a converted Stoic philosopher who took charge of the school at Alexandria in 170 A.D., introduced a wide range of studies into the curriculum and made use of his old learning to illustrate and defend his new faith.[50] Pantaenus was succeeded by two of the most noted of the Fathers of the Early Church, Clement, who was formerly his assistant, and Origen, who assumed the direction of the Catechetical School at the age of eighteen years.[51] (3) Bishop's Schools. The origin of these schools may be traced to the fact that circumstances compelled Origen to leave Alexandria in 231. Subsequently, at the invitation of two bishops, he opened a school at Caesarea. It proved so successful that similar schools were opened at a number of centres. Teaching was carried out either by the bishops in person, or by a deputy appointed by them. To these schools came candidates for ordination, the younger clergy whose instruction needed to be continued, as well as those who, for some reason or other, wished to avail themselves of the educational facilities thus provided. One other type of educational institution must also be referred to. We have already indicated the service rendered to the Church by St. Augustine of Hippo in connection with the establishment of collegiate churches, and it is equally important to note his contribution to the educational organisation of the Church. Prior to his conversion to Christianity, St. Augustine had been a teacher of rhetoric, and was the author of certain treatises dealing with the seven liberal arts. Subsequent to his consecration to the episcopate, he established a seminary for those who were in course of preparation for ordination. This seminary, though planned on community lines, was essentially an educational establishment with the avowed object of making its members as efficient as possible in the ministry which awaited them.[52] The institution proved a great success. Many priests, who were trained there, subsequently became well-known; the seminary itself furnished a model to be imitated by various bishops.[53] Ultimately, this idea of St. Augustine's was adopted by Pope Leo I.;[54] and the example thus set by Rome was followed by several bishops in Gaul, notably by Sidonius Apollinaris, Bishop of Clermont, St. Hilary, Bishop of Arles, and Gregory, Bishop of Tours. The schools established by the bishops in Gaul are of special interest to us, because the first available reference to education in this country is the statement by Bede that Sigebert "wishing to imitate what he had seen well ordered among the Gauls" "instituit scolam in qua pueri litteris erudirentur."[55] It is consequently necessary that we should next turn to the educational system of Gaul at this time.