In every Greek orchestra there was an altar of Dionysus. The fact is proved by the express testimony of ancient writers, and also by the circumstance that the dramatic performances were preceded by a sacrifice.[366] However, there is only one theatre, that of Priene, in which any remains of an altar have been discovered. In this theatre, which was excavated for the first time in the year 1897, the altar is still found standing in its original position. It is placed just in front of the first row of seats, and exactly opposite the centre of the stage.[367] Whether this was the usual position of the altar in a Greek theatre seems doubtful. In the earliest period, when the drama was still a purely lyrical performance, the altar stood in the centre of the orchestra, and the chorus danced round about it. The evidence supplied by the remains at Athens and Epidaurus rather favours the view that in these theatres it still occupied the same position. In the middle of the theatre at Epidaurus there is a round stone, 28 inches in diameter, let into the ground, so as to be on the same level with the surrounding surface. In the middle of the stone is a circular hole. A similar hole, as we have seen, is found in the later Athenian orchestra. The only plausible explanation of these holes is that they were intended for the reception of small stone altars. It is probable, therefore, that the practice varied in regard to the situation of the altar. In some theatres, such as those of Athens and Epidaurus, it may have been placed in the middle of the orchestra, after the ancient fashion. In others, such as that of Priene, it may have been drawn further back towards the auditorium, so as to leave a clear space for the evolutions of the chorus. The altar of the theatre was called the Thymele, because of the sacrifices offered upon it. It is called by this name in a fragment of Pratinas.[368] In later times the use of the word was extended, so as to denote, not only the altar, but also the space round about it; and ‘thymele’ became a regular name for an orchestra.[369] Later still, when the Romans substituted the stage for the orchestra, the word ‘thymele’, having become identical in meaning with the word ‘orchestra’, was employed in similar fashion to signify the ‘stage’.[370]