In June 1053 Pope Leo IX moved to Apulia, and reached the Fortore river near the city of Civitate. The Normans went forth to intercept the Papal army near Civitella and prevent its union with the Byzantine army, led by Argyrus Catepan of Italy. The Normans were short on supplies and had fewer men than their enemies, with no more than 3,000 horsemen and a few infantry against 6,000 horsemen and infantry. They asked for a truce, but before the negotiations ended, they attacked the Papal army.
In the ensuing battle the Norman army prevailed thanks to the military genius and bravery of Robert Guiscard and the Pope was captured by him...
The battle lead to an end of the Byzantine presence in South Italy which was flooded by Normans...
WI the Papal army had joined the Byzantine army and Normans were crushed? How is that altering History? Could a joint Byzantine-Papal victory butterflied away the Schism between Churches? Any thoughts?