Classical drama are either tragic or purely comic, but not a mixture of the two, and there should be not sub-plot or episodes uncompensated with the main theme. In other words, actions or events the play should be confined to ones species and one single plot to ensure verisimilitude. The incidents must all be logically connected. The Unity of place is a natural corollary of the Unity of time. If the play must limit itself to event that covers only a few hours, it must be confined to one place, the scene must be such as might be conceivable with the short time allowed to the action of the plot.