After determining the battle strategy, the Persian and Jin coalition forces soon moved according to plan. Since they had torn their faces with the Romans, the Persians were not ambiguous and decided to start a war first. Přidore personally led the main army to besiege Nisibis and Hatra.

At the same time, in order to contain the Romans, the Persians also took advantage of the strong mobility of cavalry, bypassing the fortified cities and invading Roman Syria and Cappadocia, and were busy attacking the cities.

The Persian invasion was soon met with a resolute counterattack from the Romans. The Roman Emperor Constantine the Great immediately mobilized the main army of the Roman Empire to the East, ready to teach the Persians a hard lesson, and even he himself planned to conquer Persia himself.

In view of the characteristics of the Sassanid army, the staff formulated a three-way offensive plan for Constantine. The three routes were: the northern route, which advanced northeastward, passed through Armenia, and enlisted the Armenian heavy cavalry, the pride of its army, to join forces and continue eastward to invade the region of Achopetini (Iranian Azerbaijan), and then move eastwards to Ray (Tehran, Iran), or southeast to the Medes and follow the valley of the Lesser Zab or Diyala rivers south to the plain of the two rivers.

The south road, southeast down the Euphrates, crosses the two rivers north of the confluence of the two rivers, and points towards Susa. The Romans chose to cross the river here because the confluence of the two rivers was a swamp that was impassable. The basin of the two rivers is rare in the world, and the estuary does not have large rivers in large cities, because there are swamps and saline-alkali lands everywhere.

In the middle, it was the main army commanded by Emperor Constantine. He did not follow the path of Alexander and Crassus of Macedonia, but crossed the Euphrates and went straight to Zingara, pointing to Ctesiphon.

According to the battle plan of the Romans, in order to achieve their strategic intentions, they could not do without a large number of troops. However, the three-way army did not go hand in hand, but there was a time difference. The northern route went first, marching in the mountains and plateaus throughout the whole process, attracting the main force of the Persian army to the north. If the Persians come to war. Then the Roman heavy infantry had an advantage in mountain warfare. Not afraid of your heavy cavalry. If the Persians don't fight, it doesn't matter, as long as they contain you here.

Rear on the south road, make a gesture of attacking Ctesiphon. Even if the Persians broke the Roman Northern Route Army. Thousands of miles over the mountains and wading through the water. It is also 'fifty miles and fighting for profit, then the general'.

The middle army was the last to advance, and the Persians were tired of running north and south in their territory. The main forces of the Roman army also came, and whether the Persians were willing to fight a decisive battle or not, victory was in the bag. It's just that the Romans had good ideas, but sometimes the reality was often unexpected.

In the summer of 313 AD, the Northern Route Army first set out as planned, joined the Armenian army, and smoothly entered the Achopetini region along the rugged mountain road, and then went south, all the way to the Medes. Here, they met Pusedor, who had received information and had led his army north.

Faced with the rugged terrain of the Medes, the Persian cavalry did not rush to attack, because to do so would be suicide. The Romans were also in no hurry to attack, because they were facing the main Sassanid force, and as long as they achieved the goal of containment, they would complete the task, so they set up a large camp and held out in the deep ditch and high fortress.

Just when the main Persian army hesitated, Pusedor received a report from the Roman Southern Route Army, so he immediately left the infantry to monitor the enemy, and then led all the cavalry to the south quickly, quietly attacking the Roman Southern Route Army.

Unlike the Northern Route Army, which trekked hard in the mountains, the Roman Southern Route Army did not encounter any organized low-grade along the way, and flew southeast along the Peacock Road along the Euphrates Plain.

Because it was too smooth, the Roman army on the southern route thought that the Sassanids were not vulnerable at all, and some Romans even thought that the Persians were either far away or were wiped out or pinned down by the northern route.

When this loose and crumbling army encountered the real Persian heavy cavalry that suddenly appeared in front of them, it was too late to form a combat formation, and after the downpour of arrows, the Persian heavy cavalry attacked in the center, and the light cavalry outflanked left and right, and the Roman army on the southern route was wiped out in an instant.

Although the Great Jin Expeditionary Force did not participate in this battle, the Great Jin military observers accompanying Psuidor were fortunate enough to witness the power of the Persian heavy cavalry. The power of the Persian heavy cavalry shocked the observers, and it turned out that the Persians also had their own killer skills.

After the war, the Great Jin observer recorded in detail the armor and weapons of the Persian heavy cavalry: "The whole body of the Persian cavalry was covered with iron tools, the thick armor covered every part of the body, the joints of the armor were well connected to the limbs, and the face of the armor was well made and matched the head of the knight." Since his body was completely covered in metal, the knight could only see through small openings in the closed pupils, and breathing could only be done through the tip of his nose. These cavalrymen were armed with spears, and they stood motionless like a mountain, one might think that they were held in place by a pile of metal. ”

Military observers even believe that without the coordination of artillery, the infantry of the Xiang Army is likely to be completely annihilated in the event of an onslaught of massive Persian heavy cavalry. Of course, he didn't have much to worry about, not to mention the powerful artillery in the Xiang army, the power of the heavy cavalry of the Jin army alone was not inferior to that of the other party.

The victory of Persia in the first battle made Percidore overjoyed, and he was full of confidence in the future wars. As a Persian, Percidore was well aware of the Persian desire for Armenia. If he succeeded in taking Armenia this time, it would certainly give him great prestige, which would be very beneficial to the consolidation of his rule in Persia.

It can be seen from the topographic map that the terrain of Armenia is higher than the plain of the two rivers, showing the trend of high buildings, or the birthplace of the two rivers, according to the Chinese feng shui, Armenia is 'the wind and water' of the two river basins, Armenians fart, Persians have to smell, Armenians wash their feet, Persians have to drink people's foot-washing water.

If the valley of the two rivers is Eastern Wu, Armenia is Jingzhou, and without Jingzhou, Sun Quan will be restless; In the same way, without control of Armenia, the Persians will not be able to turn a blind eye.

To paraphrase the above analogy of Eastern Wu, Persia is the state of Wu, then the Roman Empire is the state of Wei, the bottom river is the Yangtze River of Persia, the young river is the Huai River, and Armenia is Jingzhou where Guan Yu is located. The city of Rome is too far away, and Antioch, as the Asian capital of Rome, is equivalent to Luoyang. Edessa is equivalent to Xiangfan, and Nisibis is equivalent to Xiaoyaojin.

Now that Pusedor's army besieged Nisibis and eliminated the Roman army in the center, he had temporarily gained the upper hand. However, the Romans were not easy to mess with, and when Constantine learned of the defeat of the Southern Route Army, he immediately and decisively halted his advance. But the Romans apparently underestimated the speed of the Persian reaction, and the Persian sniper troops, who had been hovering near the Tigris, immediately crossed the river and attacked the Romans in the center.

This time, the Great Jin Expeditionary Force was also fortunate to move with the Persians, and the coalition forces successfully surrounded the Romans. Faced with such a grim situation, the Roman Emperor Constantine was disillusioned with his generals and ministers. The Persians, on the other hand, were ecstatic, and the commander of the coalition forces, General Russell, immediately took advantage of the Romans' hesitation and commanded the Persian army to launch a sudden and fierce attack.

The tactics of the Persians were still old-fashioned and practical, and they warmed up with a rain of arrows, killing and wounding the Romans in large numbers, and while the enemy army was shaking, the Persian heavy cavalry put away their bows and arrows, raised their spears and launched a charge, and trampled the Roman infantry. All of a sudden, the battlefield turned into an Asura hell, with the corpses of the Romans strewn across the field, seeing severed arms and stumps, and hearing the moans and wails of wounded soldiers.

However, after all, this Roman army was numerous, and Constantine was not incompetent, so he took advantage of the slaughter of the outer troops to quickly organize the inner Roman soldiers into battle formation. In this way, the Romans gained precious respite at the expense of the outer troops, and the Roman soldiers on the inner side soon erected their shields under the command of the officers, forming a dense shield wall, like a fortified castle, to withstand the rain of Persian arrows and the onslaught of Persian cavalry.

The reaction of the Romans also shocked the expeditionary generals, and the enemy army was indeed a well-trained force. Otherwise, it would not have been possible to react so decisively and quickly in a desperate situation. Even many officers and soldiers of the expeditionary force saw a trace of the figure of the van army from the Roman soldiers, the same professionalism, the same training, and the same discipline!

As the Romans rallied into battle formations, the scales of war began to tilt in favor of each other. You must know that the Persian cavalry is not equipped with stirrups like the box army, and the heavy cavalry in the era without stirrups has limited impact power, and does not have much advantage in the face of well-organized hoplites.

After several deadly but non-stoppable charges by the Persian heavy cavalry against the Roman shield wall, General Russell had to order a halt to the needless assault and instead shoot arrows at the Romans inside the shield wall, who returned fire with their own bows and arrows.

For a time, the battle was at a stalemate. Although the Roman army fought away from home, they were numerous, and if the Persians could not destroy the other side in a short time, they were likely to retreat to the city of Hatra near the border, and once the other side fled there, the Persians would not find such a good opportunity to destroy the enemy.

Seeing the stalemate on the battlefield, the commander of the expeditionary force, Captain Beigong Chun, realized that it was the turn of the Jin army to fight, Beigong Chun was born in Liangzhou and was valued by Zhang Liang, and was later recommended by him to study at the Chang'an Army Officer Academy, and did not graduate until last year. Because of his own courage and outstanding academics, he was valued by Sima Shu as soon as he graduated, and this time he was awarded the great responsibility of commander of the expeditionary force.

"Captain Beigong, my general asks you to fight!" Sure enough, it didn't take long for a Persian herald to convey the order of the main general Russell to Beigong Chun. Beigong Chun did not hesitate, and immediately began to straighten out the soldiers and horses, ready to attack! (To be continued......)