This was after the dogmatic tendency of the Academy under Antiochus and his followers had driven Pyrrhonism from the partial union with the Academy, which it had experienced after the breaking up of the school under the immediate successors of Timon. Aenesidemus taught about the time of our era in Alexandria, and established the school there anew; and his followers are spoken of in a way that presupposes their continuing in the same place. There is every reason to think that the connection of Sextus with Alexandria was an intimate one, not only because Alexandria had been for so long a time the seat of Pyrrhonism, but also from internal evidence from his writings and their subsequent historical influence; and yet the _Hypotyposes_ could not have been delivered in Alexandria, as he often refers to that place in comparison with the place where he was then speaking. He says, furthermore, that he teaches in the same place where his master taught.[1] [Greek: Blepon te hoti entha ho huphaegaetaes ho emos dielegeto, entautha ego nun dialegomai]. Therefore the school must have been removed from Alexandria, in or before the time of the teacher of Sextus, to some other centre. The _Hypotyposes_ are from beginning to end a direct attack on the Dogmatics; therefore Sextus must have taught either in some city where the dogmatic philosophy was strong, or in some rival philosophical centre. The _Hypotyposes_ show also that the writer had access to some large library. Alexandria, Rome and Athens are the three places the most probable for selection for such a purpose. For whatever reason the seat of the school was removed from Alexandria by the master of Sextus, or by himself, from the place where it had so long been united with the Empirical School of medicine, Athens would seem the most suitable city for its recontinuance, in the land where Pyrrhonism first had its birth. Sextus, however, in one instance, in referring to things invisible because of their outward relations, says in illustration, "as the city of Athens is invisible to us at present."[2] In other places also he contrasts the Athenians with the people whom he is addressing, equally with the Alexandrians, thus putting Athens as well as Alexandria out of the question. [1] _Hyp._ III. 120. [2] _Hyp._ II. 98.