Heraklonas

Constantinus Heraclius, known to history as Heraklonas (626-641), was the son of the Byzantine Emperor Herakleios and his second wife Martina. He was co-emperor with his half-brother Constantine III for four months in 641 until Constantine's untimely death. Heraklonas ascended, but certain factions sought to check Martina's influence on the throne by forcing Constans II as co-emperor. By September, 641, however, a revolt broke out against Heraklonas and his mother. Constans II was made emperor, and both Heraklonas and Martina were sent into exile. Heraklonas' nose was removed, the first time a Byzantine Emperor was mutilated.

Heraklonas' death is unrecorded, although it appears he died before the year was out.

Heraklonas in Justinian
In his memoir, Justinian II briefly recounted Heraklonas'  overthrow. He also approved of Heraklonas' mutilation, ironic given Justinian's ultimate fate.