Martina (died after 641) was the second Empress consort of the Byzantine Empire by marriage to Heraclius, and Regent in 641 with her son. She was a daughter of Maria, Heraclius' sister, and a certain Martinus. Maria and Heraclius were children of Heraclius the Elder and his wife Epiphania according to the chronicle of Theophanes the Confessor.
Eudokia, first wife of Heraclius, died on 13 August 612. According to the Chronographikon syntomon of Ecumenical Patriarch Nikephoros I of Constantinople, the cause of death was epilepsy.
According to Theophanes, Martina married her maternal uncle not long after, placing the marriage in 613 at the latest. However Nikephoros places the marriage during the wars with the Eurasian Avars which took place in the 620s.
The marriage was considered to fall within the prohibited degree of kinship, according to the rules of Chalcedonian Christianity concerning incest. This particular case of marriage between an uncle and a niece had been declared legal since the time of the Codex Theodosianus. Thus the marriage was disapproved by the people of Constantinople and the Church.
Despite his disapproval and attempts to convince Heraclius to repudiate Martina, Patriarch Sergius I of Constantinople performed the ceremony himself and crowned Martina in the Augustaeum after she was proclaimed Augusta by Heraclius. Even the members of the imperial family voiced their objections, with Heraclius' brother (and Martina's uncle) Theodore continually criticising Heraclius.
The Emperor and the Empress were, however, clearly a close couple: Martina accompanied her husband in his most difficult campaigns against the Sassanid Empire. She was also at his side at Antioch when the news was received of the serious defeat by the Arabs at the river Yarmuk in August 636.
On his deathbed in 641, Heraclius left the empire to both his son from the first marriage, Heraclius Constantine (as Constantine III), and Heraklonas (as Heraclius II), his son with Martina, granting them equal rank. Martina was to be honoured as empress and mother of both of them.
Heraclius died on 11 February 641 of an edema which Nikephoros considered a divine punishment for his sinful marriage. Three days later Martina took the initiative in announcing the contents of Heraclius' will in a public ceremony. The authority for such a ceremony typically belonged to the succeeding Emperor, not to the Empress. Martina was attempting to establish her own authority over the two co-emperors.
The ceremony took place in the Hippodrome of Constantinople. Present were members of the Byzantine Senate, other dignitaries and the crowds of Constantinople. Absent were both Constantine and Heraklonas. Martina read the contents of the will and claimed the senior authority in the Empire for herself. However the crowd instead acclaimed the names of the two Emperors and not her own, thus objecting to her assumption of imperial authority. She was forced to return to the palace in defeat.
Relations of Martina and her stepson were always difficult. When Constantine III died suddenly of tuberculosis only four months later, the common belief was that the Empress poisoned him to leave Heraklonas as sole ruler. Also Martina began immediately to exile the prominent supporters of Constantine and with the help of Patriarch Pyrrhus I of Constantinople, one of her primary advisors, revived the policy of Monothelitism.
Her actions and the rumors of poisoning Constantine III caused the people and the Senate to turn against Martina and her son. The Armenian Valentinus with the troops from Asia Minor, marched to Chalcedon and a frightened Heraklonas named Constans II, son of late Constantine III, a co-emperor.
This, however, failed to ease the discontent and by the end of the month the Byzantine Senate deposed him. His nose was slit, Martina's tongue cut out and they were exiled to Rhodes. Constans II became sole emperor.
Martina and Heraclius had at least 10 children, though the names and order of these children are questions for debate:
- Constantine. Named a Caesar in 615. Died young.
- Fabius, who had a paralyzed neck. Died young.
- Theodosios, who was a deaf-mute, married Nike, daughter of Persian general Shahrbaraz.
- Heracleonas, Emperor 638–641.
- David (Tiberios) (born on 7 November 630), proclaimed Caesar in 638. He was briefly proclaimed Augustus and co-emperor with Heraklonas and Constans in 641. Deposed, mutilated and exiled to Rhodes.
- Marinus. A Caesar. Died after being circumcised according to John of Nikiu.
- Augoustina. Proclaimed an Augusta in 638.
- Anastasia and/or Martina. Proclaimed Augusta in 638.
Of these at least two were handicapped, which was seen as punishment for the illegality of the marriage and may have been a consequence of inbreeding.