To recover from a seemingly endless number of defeats, Heraclius went about a reconstruction plan of the military, financing it by fining those accused of corruption, increasing taxes, and debasing the currency to pay more soldiers and forced loans.
The Patriarch of Constantinople, Sergius, placed the finances of the Church into the hands of the State, a surprising but well-needed sacrifice.
Heraclius now aimed to eliminate one of his dangerous foes, the Sassanid Empire.
The Persians had conquered extensive amounts of territory in Anatolia, Mesopotamia, the Levant, and North Africa, but had yet to consolidate their hold on it.
Heraclius decided to negotiate a peace with the Avars and Slavs by paying them a large amount of tribute so that he could freely move his armies from Europe to Asia in order to launch counter-offensives against the Persians.
With his Eastern opponents still outside Chalcedon, in the spring of 622 Heraclius took the field.
He sailed his newly created army down the Ionian coast and landed at Issus, the exact site where Alexander the Great had decisively defeated the Persians some 1,000 years prior.
At Issus, Heraclius oversaw the extensive training of his men.
In the autumn of that year, he marched his army northwards and encountered a Persian force in the Cappadocian highlands.
Despite having no military experience in leading an army in the field, the Byzantine Emperor decisively routed the forces of the experienced Persian General Shahrbaraz, boosting his army's morale and recovering large amounts of territory.

In early 623, Heraclius led his forces through Armenia and modern-day Azerbaijan.
By moving towards Armenia, this forced the Persians to move from their positions in Asia Minor and to follow the army "like a dog on a chain".
It was in Armenia that the Byzantine army once again found success against the Persian general Shahrbaraz, winning a large victory.
Events in the capital forced Heraclius and his army to return to Constantinople, as the Avar Khan was threatening action on the city.
Heraclius was forced to increase the tribute being paid to the Avars, even having to go as far as sending hostages to the Khan to ensure payment.
This once again shored up his rearguard, allowing him to re-engage the Persian army in March 623, as the Persian king Chosroes II had become ever more belligerent in his attitude, spurning a truce.
On the way to Persia, the Byzantine army pillaged and looted extensively, including the destruction of the Persian palace at Ganzak.
Burning numerous cities of his opponents, Heraclius made a risky decision and led his troops deep within the heartland of the Sassanid Empire to Ctesiphon, the Persian capital.
However, Shahrbaraz began cutting off Heraclius' supply lines, forcing the latter to withdraw to the western shore of the Caspian Sea.
There, his second wife and niece (Martina) safely delivered a child, although the marriage was seen by many as incestuous.

In 624, Heraclius led another campaign towards Lake Van.
However, the victory that he sought would not come to him until the following year.
Leading his army through Ararat down the Arsanias River for some 200 miles (320 km) to capture the cities of Martyropolis and Amida, Heraclius finally encountered a Persian army north of the town of Adana after marching 70 miles (113 km) through Mesopotamia.
Initially, the battle went well for the Persians, as they obliterated the vanguard of the Byzantine army.
However, Heraclius then seized the initiative by launching a seemingly suicidal charge across the River Euphrates, thus turning the tide of the battle.
Even Shahrbaraz did not deny the bravery of the Emperor:
See your Emperor!
He fears these arrows and spears no more than would an anvil!

— Shahr-Baraz,
To recover from a seemingly endless number of defeats, Heraclius went about a reconstruction plan of the military, financing it by fining those accused of corruption, increasing taxes, and debasing the currency to pay more soldiers and forced loans. The Patriarch of Constantinople, Sergius, placed the finances of the Church into the hands of the State, a surprising but well-needed sacrifice. Heraclius now aimed to eliminate one of his dangerous foes, the Sassanid Empire. The Persians had conquered extensive amounts of territory in Anatolia, Mesopotamia, the Levant, and North Africa, but had yet to consolidate their hold on it. Heraclius decided to negotiate a peace with the Avars and Slavs by paying them a large amount of tribute so that he could freely move his armies from Europe to Asia in order to launch counter-offensives against the Persians. With his Eastern opponents still outside Chalcedon, in the spring of 622 Heraclius took the field. He sailed his newly created army down the Ionian coast and landed at Issus, the exact site where Alexander the Great had decisively defeated the Persians some 1,000 years prior. At Issus, Heraclius oversaw the extensive training of his men. In the autumn of that year, he marched his army northwards and encountered a Persian force in the Cappadocian highlands. Despite having no military experience in leading an army in the field, the Byzantine Emperor decisively routed the forces of the experienced Persian General Shahrbaraz, boosting his army's morale and recovering large amounts of territory.
In early 623, Heraclius led his forces through Armenia and modern-day Azerbaijan. By moving towards Armenia, this forced the Persians to move from their positions in Asia Minor and to follow the army "like a dog on a chain". It was in Armenia that the Byzantine army once again found success against the Persian general Shahrbaraz, winning a large victory. Events in the capital forced Heraclius and his army to return to Constantinople, as the Avar Khan was threatening action on the city. Heraclius was forced to increase the tribute being paid to the Avars, even having to go as far as sending hostages to the Khan to ensure payment. This once again shored up his rearguard, allowing him to re-engage the Persian army in March 623, as the Persian king Chosroes II had become ever more belligerent in his attitude, spurning a truce. On the way to Persia, the Byzantine army pillaged and looted extensively, including the destruction of the Persian palace at Ganzak. Burning numerous cities of his opponents, Heraclius made a risky decision and led his troops deep within the heartland of the Sassanid Empire to Ctesiphon, the Persian capital. However, Shahrbaraz began cutting off Heraclius' supply lines, forcing the latter to withdraw to the western shore of the Caspian Sea. There, his second wife and niece (Martina) safely delivered a child, although the marriage was seen by many as incestuous.
In 624, Heraclius led another campaign towards Lake Van. However, the victory that he sought would not come to him until the following year. Leading his army through Ararat down the Arsanias River for some 200 miles (320 km) to capture the cities of Martyropolis and Amida, Heraclius finally encountered a Persian army north of the town of Adana after marching 70 miles (113 km) through Mesopotamia. Initially, the battle went well for the Persians, as they obliterated the vanguard of the Byzantine army. However, Heraclius then seized the initiative by launching a seemingly suicidal charge across the River Euphrates, thus turning the tide of the battle. Even Shahrbaraz did not deny the bravery of the Emperor:
See your Emperor! He fears these arrows and spears no more than would an anvil!
— Shahr-Baraz,
Byzantine Empire under the Heraclian dynasty