The Relationship Between Orphism and Other Religious Movements

There's a famous definition in 1977 by Burkhart of Orphism as three circles that would be overlapping in the middle. The Bacchic mysteries, Pythagoreanism and Illusis are all important to understand what was going on there. But our evidence is really too scanned to say what was happening in southern Italy was completely different or absolutely identical with Crete or Thessaly. So why couldn't we call him an Orphic? It's a matter of how broad you want to make the term.