I just got Harry Turtledove's 'Justinian' as a late birthday present, and I just wondered what might happen if Justinian II's younger brother, Heraclius, had survived childhood. Assuming Justinian's reign sticks close to what happened OTL, might Heraclius be placed on the throne when J is mutilated and exiled or would Leontius (or whoever does the overthrowing) decide to get rid of him too?