Great to see this very useful set coming. It is my understanding that Turcopoles at some point in history formed the bulk of the Byzantine army, but also fought as mercenaries for Norman, Frankish and Latin crusader states. They were allies to Slavic and Armenian forces, mercenaries for and against the Seldjuks. They also fought against Persians and Arabs. Their most famous battles probably being the battle of Manzikert against the Seldjuk army of Alp Arslan - the 'valliant lion', and the fall of Acre, the last crusader state.
So, I think anyone who is interested in this time period should start saving up some money for the upcoming release of these figures. Cause you'll likely need a lot of them and the same is true for the other sets that Strelets has announced.