A question I get asked a lot is, "What is Classical Pilates?" The short answer is the exercises as developed by Joseph Pilates. However, since he taught for over 60 years and had many students who came with different issues and injuries, it turns out that different people have slightly different versions of what he taught them.
Another answer is the work he developed as expanded on by his students. Even this is a problem because certain of his students seem to have more "classical pilates clout" than others.
In some sense the phrase Classical Pilates is relatively meaningless. It is certainly a good marketing tool and my classical pilates friends will no doubt hate me me for saying this, but I have yet to really hear a good answer as to the definition that doesn't simply slam other Pilates teachers.