Heraklonas

Constantine Heraclius Augustus 626641, commonly known by the diminutive Heraklonas or Herakleonas , or rarely, Heraclius II, was the son of Heraclius and his niece Martina, and was Byzantine Emperor briefly between February and September 641.

Heraklonas was probably born at Lazica while his father was on campaign against Khosrau II of the Sassanid Empire. He was probably the fourth son of Martina and Herakleios, but the first one born free of physical deformity and eligible for the throne.

Source: Wikipedia