By the time that these schools began to establish themselves the Sophists were beginning to die out. Times were harder in the fourth century, and fewer people had money to spend on these expensive teachers. The intellectual movement of the Periclean age had spent itself, and the desire for universal knowledge was no longer so keen. Moreover, it is quite probable that settled schools, like that of Isokrates at Athens, were forming in many of the great centres: it is known that Isokrates himself taught for a while in Chios. The great demerit of the Sophists’ teaching, namely, that it was too much in a hurry and gave no time for personal endeavour on the part of the pupil, had been recognised: and the result was that the Sophists settled down in a single place and gave continuous courses of instruction. But a good many Sophists of the old type remained, to vex Isokrates by their criticisms and rivalries. They still came to Athens at the great festivals, and gave hurried lectures.[530] But they had not the originality of their predecessors, and people preferred to read the works of Protagoras or Gorgias for themselves to hearing them repeated as original by a lecturer. Books were already a serious rival to lecturing, and were a cause of much searching of heart to Plato: Isokrates, however, preferred to write himself and so advertise his school. Besides the wandering Sophists there were probably a good many teachers, both of Philosophy and of Rhetoric, established permanently at Athens. Isokrates mentions casually that all the schools[531] produce only two or three first-class speakers. In his educational prospectus, _Against the Sophists_, he criticises these rivals freely. “They merely try to attract pupils by low fees and big promises. The speeches which they write themselves are worse than the improvisations of the wholly untrained, yet they promise to make a complete orator out of any one who comes to them; for they make no allowance for natural talent or for experience, but regard eloquence as an exact science, just like the A B C and equally communicable; whereas it is really a progressive art, where the same thing must never be said twice, and its rules must be relative to the occasion and the circumstances.”[532] It is clear that these rivals committed the serious crime of underselling Isokrates and also of issuing more attractive prospectuses; perhaps, too, they are the captious critics to whom he is always referring.