Hearing that Michael had returned from Sicily the Normans prepared themselves for battle; although the forces of the Greeks were many and their own people few, for they had an army of but five hundred infantry and seven hundred knights.  Only a few were protected by hauberks and shields. The foot soldiers were advised to station themselves on the left and right flanks; a few horsemen were posted with them to provide a reinforcement to stiffen the footmen. They were absolutely forbidden to leave the field. If they were forced to retire by the enemy they were to regroup. After these troops had been thus instructed and placed on each flank, a column of cavalry advanced a little way forward. A column of Greeks was sent out against them, for it is not their custom to engage all their forces at the first shock,  they rather send another troop after the first, so that as the enemy weakens their own strength increases and their troops are emboldened. So, when their cavalry commander sees the enemy resisting, he makes a sudden attack with the bulk of the remaining crack troops, thus restoring the morale of his own men and usually driving the enemy back in flight.
The two armies faced each other and a great battle was fought next to the fast-flowing River Olivento. The Greeks were  defeated and the army of the Gauls pursued them vigorously. Many dead bodies lay on this Apulian plain, but more were engulfed by the river. Some of the Greeks were seized by panic and fled quivering with fear; neither rough ground nor the river’s flood stopped their headlong flight. More of the Greeks drowned in the river than died by the sword. The Gauls speared some and cut down others with their swords, and in various ways a huge number of Greeks were killed. Michael escaped with a few men and went to a mountain, from the summit of which one could overlook the neighbouring hills.  This victory greatly strengthened the morale of the Gauls, and from now on they no longer feared to fight the Greeks. In the same way a hawk which is accustomed to seize small birds hesitates to attack one bigger than itself, but if it should succeed in conquering a crane then henceforth it no longer fears [even] a swan nor is in awe of any big bird.
Raising a new Greek army, Michael led all the men he could collect with him to the river of Canne, which is called the Ofanto.  The Gauls returned to the fight. Michael was defeated by them as he had been before. The Greeks were conquered and many of them were killed. Dokianos was thrown from his horse during his flight and his life was only saved through the assistance of his groom. His horse rushed madly into the river and Michael all but fell into the hands of his enemies, but for his servant giving him his own horse. With their good fortune in battle becoming even greater, the Normans grew more confident still. Michael retired to the heights of Montepeloso,  from where he sent a message to the army which the Greeks had then in Sicily, telling them to come and replace the troops that he lacked after his defeat at the enemy’s hands.
The victorious Normans decided to return to Melfi. They remained there for a while in peace and quiet with the booty which they had gained from the Greeks. Twelve squares were laid out, one for each of the counts, and the same number of houses was built for them in the city. But since earthly honours always rouse humans to envy, the fierce Gauls [soon] refused to obey the orders of the counts whom they themselves had selected.  They preferred rather to have as their head a native Italian rather than one of their own race. He was called Atenulf, Prince of Benevento. He had perhaps given them gold or silver and thus led them to go back on the prior agreement. What will a desire for money not compel men to do, for it can change the mind of the trustworthy and overturn the bond of the law-abiding?
After the Sicilian army had received the messages from  Dokianos demanding reinforcements, and realised that he was in need of their help, they hastened to recruit men from every part of Calabria, that they might revenge their men whose bodies lay unburied in field or river. With the Greeks were some madmen who profess the dreadful error, from which they derive their name, of saying that the Father had suffered with the Son, and they make the sign of the Cross on their forehead with a single finger. They teach that the Father, Son and Holy Spirit are one and the same person. These hastened together to battle, all driven by one thought, to replace the forces which Michael had lost. However the ruler to whose care the Roman Empire was entrusted forbade  Michael to lead his army any longer, since he had been unable to secure any sort of success against the Normans. The Emperor ordered Exaugustus to undertake this office and to lead the Greeks in battle. It was said that his father was the victorious Basil, who had forced the Gauls to flee when Melus had led them. Michael Dokianos meanwhile returned to Sicily.
 He returned before March 1041.
 The battle took place on 17th March 1041 and after the battle Michael fled to Montepeloso. The Annales Barenses, sub anno 1041 said that there were 18,000 Greeks and 2,000 Normans while Geoffrey Malaterra provides more inflated figures of 60,000 Greeks and 500 Normans.
 On 4th May 1041 the Normans defeated a much larger Greek army at Canne, not far from the coastal town of Barletta. Some two thousand Greeks were killed including Angelus Presbyter, bishop of Troia and Stephen, bishop of Acherontius. Michael again retreated to Montepeloso but returned to Sicily once Maniakes arrived in Apulia in April 1042: Annales Barensis, sub anno 1041.
 Fresh from their triumphs the Norman conquerors met at Melfi, captured in March 1041 at the beginning of the rebellion, to discuss the division of the land that from Monte Gargano to Monopoli, they claimed as theirs by the right of the sword. Twelve counts were chosen to govern and the country was divided among the twelve: thus Rainulf received Monte Gargano; Drogo, Venosa; and, William, Ascoli. The fortified hill of Melfi was chosen as the common capital of the Apulian Normans. William, the eldest son of Tancred was later elected Count of Apulia, with power to make or propose new baronies as the land was further conquered. The Normans conferred the empty title of Duke of Apulia and Calabria on Guaimar. He was to give his name to the land grants of the new Count, and might exact military service; on his part he gave his niece, daughter of the Count of Sorrento to William in marriage, and the son of Tancred, like Rainulf, entered into a valuable marital relationship with one of the established Lombard families.
 Arduin enlisted the support of Rainulf of Aversa and Adenulf of Benevento was ‘elected’ (he almost certainly used bribes) to become leader of the Normans. However, conflict between the Normans and prince Atenulf over ransoming prisoners taken at Montepeloso resulted in the Normans electing Argyrus their leader at Bari in February 1042.
 There is a difference between William of Apulia’s account that dated the establishment of the counts in Melfi in 1041 and those of Leo Marsicanus and Amatus of Montecassino who dated it in September the following year. A plausible chronology that may help to resolve this problem is: September 1041 Adenulf of Benevento ‘elected’ as leader of the Normans; February 1042 Argyrus replaced Adenulf; in September 1042; following the desertion of Argyrus to the Byzantine side, William is elected count; and, the following February 1043 the Normans accepted the tacit lordship of Guaimar IV of Salerno to obtain official recognition of their concquest.
 The Paulicians were regarded as heretical and were persecuted in the ninth and tenth centuries. Under the emperor Nichephorus Phocas, some Armenians were settled in Calabria and it is almost certain that William of Apulia is referring to them at this point.
 The Byzantines now only controlled the southern part of Apulia but the rebel campaign appears to have stalled and both sides devoted the summer of 1041 to building up their strength. The Greeks transferred troops from Sicily and Calabria; Michael Dokeianos was replaced as catepan by Exaugustus, the son of the former governor Basil Boiannes. Martin, Jean-Marie, ‘L’attitude et le role des Normands dans l’Italie méridionale Byzantine’, Les Normands en Méditerraneé, (University of Caen), 1994, pp. 111-122 provides some valuable comments on this issue.