When Alexius learned that Robert had crossed the sea, he strove to regroup his battered forces and to destroy the camp of the absent duke, which was guarded by the latter’s son Bohemond  and Brienne, two men who were mighty both in battle and in counsel. Alexius’s army established its camp not far from Janina, a city of no little renown. He protected it with several rows of wagons drawn up on the side facing the plain,  which was the easiest way of approach. He obstructed all the access routes with iron calthrops to pierce the hooves of their enemies’ horses as they charged along with the reins loose. But the Greeks’ vision was ruined by fog, and the Normans arrived there unseen through difficult paths filled with  vines and dense with sedges. Alexius came to grips with them and for a while fought back, but could not resist their attack for very long. He sought flight and retired defeated.  Vanquished in a second battle, he retired to a famous town in Thessaly, called Salonika by the vulgar. However, since he knew that the fortunes of war are changeable, he prepared to return once more to the fray.
Bohemond rejoiced at having an army more brave than numerous, and exulted  in the capture of Tziviskos. He besieged Larissa, a celebrated place, which he knew to be filled with riches since the imperial treasury had been brought there. It was the birthplace of Achilles, the destroyer of Troy. The siege of this town concerned  Alexius, and he came there with a very large force and valiantly gave battle to the Normans. The troops of Brienne resisted him but were defeated. Seeing the hills swarming with this great army, Bohemond realised that the empire’s ruler was present in person.  He charged [against him] and pursued his craven enemies, as a hawk does larks. The Greek army turned tail in the face of his men, but a dust storm enveloped both sides so thick that neither could see where the other was.  The defeated Greeks sought refuge in the depths of the forest, while the conqueror, after killing some of them, returned to the mountains, there to wait in case further battles were to be levied against him.
Learning that his enemies had moved off, Alexius went to the  camp at Larissa with a large force. The infantry who had been left in the camp were unable to fight off the enemy who so outnumbered them. Most of them were killed; a small number managed to flee. Alexius captured the booty which the victorious army had brought there from all sorts of places.  A messenger hastened to the hills to bring news of the disaster to Bohemond, who (having believed himself the victor) lamented the destruction of part of his army. However, he was not the least afraid and strove to rally his disorganised troops. No setback could sap this man’s courage.  But he was annoyed to have to raise the siege of a town which was almost conquered and ready to submit. Night fell and reminded men tired out by battle to compose their limbs for sleep. Bohemond went to a sheltered valley not far from there which furnished all that was necessary for him and his men, and  there they abandoned their bodies to sleep.
After three days two noblemen led out a very large force of Greeks ready to do battle  against Bohemond; one of these was the emperor’s brother Adrian, the other his brother-in-law Melisianos. Recovering their usual courage the Normans rushed to their arms; the Greeks, accustomed to run in coward flight, hastily returned to the walls of the city of Larissa, where Alexius had taken refuge.  They had been defeated so many times that they did not dare to stray far from these. The Turks too took flight and were trapped in the city. But the Normans could not remain besieging them for very long since the land there had been so ravaged that it could no longer feed them, and their supplies had been lost when their camp had been captured. Dividing his army,  Bohemond went to Valona to find food, while Brienne went to Castoria. Alexius left most of his troops at Salonica, but he himself returned to his capital city which bears the name of its founder, Constantine.
 Alexius left Constantinople in May 1082.
 Bohemond arrived at Janina from Castoria. He defeated Alexius in two battles before Janina who then returned to Constantinople to get new troops.
 Bohemond occupied Albania and Thessaly in the summer of 1082. He then moved with all his army to besiege Trikkala and sent a detachment to occupy Tziviskos.
 Anna Comnena said that Bohemond took Larissa in the autumn of 1082 with the intention of wintering there. The siege lasted six months according to her account. However Chalandon argued that Bohemond wintered before Larissa but did not actively besiege it until the spring of 1083.
 Alexius, alerted by Leo Kephalas governor of Larissa arrived to relieve the siege. Bohemond gave command of part of the army to Brienne while Alexius gave command to Nicephorus Melissenos and Basil Kourtikios and ordered them to retreat. This stratagem worked and Bohemond split his forces and Alexius was able to defeat the divided forces and take their camp.
 Nicephorus Melissenos was married to Alexius Comnenus’ sister Eudocia.
 The Norman counts, bribed by Alexius, demanded that Bohemond go to Italy to get their pay. He left Castoria under Brienne’s control, a town occupied after the fall of Durazzo by Bohemond’s troops. Alexius then returned and took Castoria in October or November 1083. The Normans who surrendered transferred their allegiance to Alexius apart from Brienne who was freed on condition that he did not take arms again against the Byzantine Empire.