The poet was assisted in his task by a subordinate, who looked after the routine part of the work, and was called a hypodidaskalos, or ‘assistant teacher’. This was the proper term to denote the professional trainer, as opposed to the didaskalos, or poet.[247] But towards the end of the fifth and the beginning of the fourth century the practice in these matters underwent a change. Poetry and stage-management began to be sharply discriminated from one another. A class of literary dramatic writers arose, such as Theodectes and Aphareus, who were quite as much rhetoricians as poets. They knew nothing about the details of training a chorus, or preparing a play for representation. In these circumstances the greater part of the management was undertaken by the professional instructor. The term didaskalos, which had originally been confined to the poet, was now applied to these hired trainers.[248] A class of men came into existence who made choral instruction their regular business. One of these, named Sannio, is mentioned by Demosthenes, and was celebrated for his skill in training tragic choruses.[249] These professional teachers were hired and paid by the choregus. A rich choregus had a great advantage in being able to secure the best assistance. Xenophon mentions the case of a certain choregus called Antisthenes, who knew little or nothing about music and choruses himself, but was always successful in his competitions, because he took care to provide himself with the most skilful trainers procurable.[250] It is obvious that in these later times, when the poets ceased to attend to the details of stage-management, the importance of the professional trainers must have been very much increased. The hiring of a good trainer would be one of the first conditions of success. § 5. _The Expenses of the Choregia._