Aenesidemus is considered one of the major skeptic ancient philosophers but according to wikipedia little is known about his life.
How is it known that Aenesidemus the major sceptic philosopher was from Knossos?
According to The Stanford Encyclopedia of Philosophy, Anna-Barnes (1985) notes that Sextus Empiricus ascribes the 10 Modes of Scepticism to Aenesidemus.
The Stanford Entry also notes that Aenesidemus was involved with The Academy, becoming discontented with the dogmatic proto-externalism found therein.
I suppose one could search the writings / histories of other members of the academy at the time Aenesidemus was involved in order to find evidence of an "Aenesidemus of Knossos".