Currently, the legions are created through the Soissons province reclaimation events. The Byzantine Empire currently has legions in place for the provinces. I'd also like to ask how I can make the province levies unavailable, and then available when the Themata is created. And what would be the causes of the Themata creation, and what would the benefits be? Could it be tied to a special law, that only the Byzantine have, that triggers a Themata's creation, but once it is chosen, there is no coming back. Or are laws hardcoded.