The type of theatre described above was of course only developed very gradually by the Athenians. It came into existence side by side with the growth of their drama. At first there was no permanent theatre. Attic tragedy grew out of the dithyrambs performed by choruses in honour of Dionysus. For such exhibitions all that was required was an orchestra, or circular dancing-place. The chorus performed in the middle, the spectators ranged themselves all round the ring. The first innovation was the introduction of a dialogue between the coryphaeus and the choreutae in the intervals of the choral odes. For the purpose of carrying on this dialogue the coryphaeus used to mount upon the sacrificial table which stood beside the altar in the centre of the orchestra.[306] Such sacrificial tables are often found in ancient vase paintings by the side of the regular altars, and were used for cutting up the victims, or for receiving various bloodless offerings such as cakes and vegetables.[307] Both the table and the altar were called by the same name, Thymele.[308] This table, on which the coryphaeus took his stand, surrounded by the choristers, was the prototype of the stage in the later Greek theatre. The next step in the development of the drama and of the theatre was the introduction of a single actor by Thespis. This actor took the part in the dialogue previously played by the coryphaeus. But the part was now much expanded and developed. The actor, instead of remaining in the centre of the orchestra throughout the performance, used to come and go, and appear in many roles in succession, using a different costume on each occasion. A booth was erected just outside the orchestra, for him to change his dress and mask in. The platform on which he stood during the delivery of the dialogue was removed from the centre of the orchestra, and placed immediately in front of the booth, to facilitate his exits and entrances. This change led inevitably to others. The chorus, which had previously stood in a circle round the coryphaeus, now drew themselves up in lines facing the actor’s platform, so as to converse with him in a natural manner. The spectators, instead of being ranged all round the orchestra, were confined to two-thirds of it. The remaining portion was taken up by the stage.