The Normans had arrived in Southern Italy in 1017, in a pilgrimage to the sanctuary of St. Michael Archangel in Monte Sant'Angelo sul Gargano (Apulia).

These warriors had been used to counter the threat posed by the Saracens, who, from their bases in Sicily, raided South Italy without much resistance from the Lombard and Byzantine rulers of the affected lands.

An abbot from Normandy, John of Fécamp, for example wrote of such local sentiments in a letter to Pope Leo himself: Hatred by the Italians for the Normans has now developed so much and become so inflamed throughout the towns of Italy that scarcely anyone of the Norman race may travel safely on his way, even he be on a devout pilgrimage, for he will be attacked, dragged off, stripped, beaten up, clapped into chains, and often indeed will give up the ghost, tormented in a squalid prison.

[1]: 114–115 The raiding activities which brought about such hatred also occurred in the see of Benevento, a deed not emphasized in the Norman chronicles, but for Pope Leo this was the more significant concern in the political instability of the region.

According to Malaterra's account, the native Lombards were responsible for the plot, and a courtier named Rito committed the deed at the castrum of Montillaro.

[2]Finally, in 1052, Leo met his relative Henry III, Holy Roman Emperor in Saxony, and asked for aid in curbing the growing Norman power.

The Prince of Benevento, Rudolf, the Duke of Gaeta, the Counts of Aquino and Teano, the Archbishop and the citizens of Amalfi — together with Lombards from Apulia, Molise, Campania, Abruzzo and Latium — answered the call of the Pope, and formed a coalition that moved against the Normans.

[9] In front of them, the Papal army was divided into two parts, with the heavy Swabian infantry on a thin and long line from the center extending to the right, and the Italian levies amassed in a mob on the left, under the command of Rudolf.

The Swabians, in the meantime, had moved to the hill, and came into contact with the Norman center and the forces of Humphrey, skirmishing with arrows and archers before entering a general melee.

Robert Guiscard, seeing his brother in danger, moved with the left wing to the hill, and succeeded in easing the Swabian pressure, and also displayed his personal bravery with the aid of the Calabrians under the command of Count Gerard.

Yet thanks to the continued Norman discipline in holding the line against the Swabians, the day was at last decided by the return of Richard's forces from pursuing the Italians, which resulted in the defeat of the Papal coalition.

[citation needed] Other sources including Malaterra indicate that the inhabitants of Civitate handed over the Pope and drove him "out of the gates," after seeing the Norman threat manifested in siege towers and earthen ramparts.

[13] According to John Julius Norwich, Leo attempted a long, passive resistance to agreeing to anything for the Normans, and was waiting for an imperial relief army from Germany.

In addition, Norwich believes that despite the lack of concrete support until later popes, Leo did eventually acknowledge the Normans as the rulers of the South in order to get a release for his freedom.

[15] More importantly, the Battle of Civitate proved to be a turning point in the fortunes of the Normans in Italy, who were able to win a victory despite their differences even among themselves, and solidifying their legitimacy in the process.