Exactly what is meant by this “five years of silence” is uncertain. Whether it denoted unquestioning and silent obedience of all commands, as it meant in the case of the Pythagoreans (if, indeed, the traditions in regard to the latter have any basis in fact), or strict secrecy as to the doctrines taught, cannot be decided. The report in regard to the Basilidians, in so far as it has any truth, probably arose on the ground of some such prohibition, which may have been made by some follower of Basilides, if not by the latter himself. A bond of secrecy would lend an air of mystery to the school, which would accord well with the character of its later teachings. But we cannot make Basilides responsible for such proceedings. Agrippa Castor, as reproduced here by Eusebius, is our sole authority for the enjoinment of silence by Basilides.