Even today many of the traditional themes are mythological in nature. Over the centuries different areas have given their own colour to the ancient classical tradition. Each of these styles has a strong regional connection and none can claim to be representative of the entire Indian subcontinent. The first benchmark is age. The second is its ability to cross ethnic boundaries, and third is class associations.
Age is the first benchmark to come to anyone's mind.
It is generally acknowledged that for something to be considered classical, it must have great age. This seems simple at first, but it begs the obvious question of how one determines age. Although the performance may not be used to determine age, we might consider using the genre. Since the genre also produces ages which are not acceptable in traditional Indian world views, most Indians would use the tradition to define age. The ability to span different ethnic groups is another common benchmark.