Michael I Palaiologos from the moment he ascended the throne, even as a usurper, set as his goal the recovery of the City and the re-establishment of the Byzantine Empire. But he tried to achieve it through diplomatic means. Seeking to end the rivalry with the Despotate of Epirus, he sent an embassy to the despot's namesake, Michael, going so far as to grant him even cities in Macedonia, which were under his control.
Michael of Epirus, however, treated the ambassadors badly and did not accept Palaiologos' proposals. The despot Michael had already, as mentioned, secured the alliance of the Latin king of Sicily, the Latin prince of Achaia, and the Latin "emperor" of Constantinople. He therefore considered that this network of alliances, combined with his own forces, allowed him to hope that he was able to crush the state of Nicaea.
Michael Palaiologos sent an embassy to both the prince of Achaia and Manfredo, king of Sicily. But none of them agreed to answer. Thus, Michael Paleologos decided to impose his will. He assembled a powerful army, numbering about 20,000 soldiers. The sources on this point do not agree with each other. According to Western, mainly sources, Palaiologos' army numbered more than 40,000 men, of which 30,000 were mercenaries.
In fact the mercenaries numbered about 6-8,000 men. The rest were Byzantine, or at least subjects of the empire. However, the Latin "Chronicle of Moreus" states that the Byzantine Army had 13,000 Hungarian mercenaries, 4,000 Serbs and Bulgarians, 2,000 Cumans, 300 German knights, excluding Turks and Greeks.
In fact there were Turkish mercenaries, few – less than 400 Serbs and Bulgarians – the Cumans and 300 Germans, under the duke of Carinthia. As far as the "Hungarians" are concerned, they were the so-called Vardarian horse archers, who were subjects of the Empire, who lived in the region of Axios (Vardaris), from where they got their name.
Toward the conflict
With this army, Emperor Michael's brother, John Palaiologos, marched to Macedonia and invaded the territories of the Despotate of Epirus. The Byzantine army of the venerable king John moved quickly, completely surprising the opponents. The Byzantine Army crossed the straits of Edessa and marched on the opponents. The despot of Epirus, Michael was at that time in Kastoria.
When he learned that the Byzantines had reached Edessa unmolested, he was terrified and fled with his entire army. In fact, in the confusion that followed, several of his men were killed in their panic to get out of the gates. John Paleologos took advantage of the opportunity and the panic of his opponents and occupied the entire area from Lake Achrid to Prespes - in the spring of 1259.
In the meantime the despot Michael had taken advantage of the time that had been given to him to gather his own troops and call upon his Latin allies to reinforce him. The king of Sicily sent him 400 knights, while Villeardin of the Morea came with his whole army, which included about 1,000 knights of the principality, who were considered the best knights in Francia.
But he also had a large number of foot soldiers, Latins, heavily armed and Greeks, small vassals. Also, the despot Michael had a strong army with his own Pronoiarians, heavy horsemen, as well as many infantry, crossbowmen and archers.
However, Villeardouin's division seems to have been outnumbered. Altogether, we do not know exactly how many men the allied army had. However, it must have been slightly superior to the corresponding Byzantine one. When the allied army gathered it moved against John. John, however, had military experience and intelligently deployed his men on the Pelagonian plain. It was the summer of 1259.
The Byzantine army was deployed in the low hills, around the plain. Detachments of heavy infantry were posted on the hills, with the heavy cavalry between them, as an agile link. In front of the heavy troops lined up, in an acrobolism formation, light cavalry, mercenary and Greek divisions and the lightly armed infantry, mainly archers and slingers.
The allied forces faced the Byzantines, but not daring to attack. So the opposing armies encamped opposite each other. This development perfectly served the plans of John Palaiologos, who wanted to wear down his opponents, without his army suffering losses. Taking advantage of the speed and agility of his light troops he began to constantly harass the allied army.
Georgios Akropolites reports factually:"Those who were blindfolded and carrying breastplates were ordered to the fortified places. And the lightly armed, who were more agile, he sent them to the plain, to fight there with the enemy. These were not Scythians – Cumans – and Turks, but also many of the Roman tribes who were skilled in the use of the bow and could hit their opponents from afar. They even began the battle from a point, which had the name Longos Borilla, constantly attacking the opponents and not allowing them to rest either day or night.
The vivid description of the Acropolis is revealing of the way the conflicts were conducted. The light troops of the Byzantine Army were constantly straining the allies, with small raids, not allowing them to calm down, or to rest, or even to water their horses. Also, with continuous raids they destroyed enemy supply convoys.
Unable to react seriously, the allies had found themselves in a highly irritating situation. Irritation, however, results in even more irritation and arguments. Thus the disputes between Greek and Latin allies soon began.
Breaking the alliance
The sources of the time state that the Latins daily had verbal conflicts with their Greek allies, due to their arrogance and the sense of superiority they had. They even went so far as to harass even the wife of the son of the despot of Epirus. Nicephorus, that was his name, became very angry and a fight almost broke out between his men and the Latins.
That same night the despot Michael and his son, Nikephoros, abandoned the Latins and left secretly. A part of their army left with them. But several of their men hastened to join John's army, as no one liked the Latins.
This development should naturally worry Villeardouinos. However, he, proud and arrogant as he was, thought that it was better that the Greeks left - whom the Latins derogatorily called "griffins", i.e. dogs - since his knights were invincible anyway. John, however, had the opposite opinion and now, reinforced with the Epirotian automoles, he attacked with his entire army, having as a vanguard the 300 German knights.
The Germans immediately accepted the counterattack of the flower of Achaean chivalry. A terrible conflict ensued. The commander of the Germans, the brave duke of Carinthia, was killed. But the Latinos did not rejoice for long. John's light cavalry surrounded them –as usual they charged forward wildly, but unorganized, according to the "chivalric ideal of the West" – and exterminated them. Dozens of Moria's knights fell from their horses and were cut down by the Byzantine infantry.
the Latin infantry, on the other hand, as soon as they saw the destruction of the knights, did not stand to fight, but fled in disorder, together with Villearduino and some other knights who had survived. The Byzantines pursued them, killed many of them and captured even more. Villeardouin hid in a haystack, but the soldiers found him and captured him, not knowing who he was. When they took him to John, he understood who was in front of him by his large teeth that protruded from his mouth.
In the meantime, the pursuit continued as far as Platamonas, as reported by the Byzantine chroniclers. Essentially, the Latin army was annihilated in its entirety, with its leaders – Villearduino, the baron of Carytaina and other nobles – being led in irons to the emperor Michael. Also captured were 393 of the 400 Italian knights sent as reinforcements by the king of Sicily. The knights were captured by the great domestic, Alexios Stratigopoulos and his men.
The victory was extremely important. John continued his victorious march, liberating most of Epirus, almost all of Thessaly and reaching Thebes. At the same time, Emperor Michael took advantage of the captivity of the Latin leaders, demanding as a ransom for their release 3 fortified castles in the Peloponnese, the castles of Mystras, Main (Manis) and Monemvasia. From there began the saga of the Despotate of Mystras and the liberation of the Peloponnese from the Frankish yoke.