Gregory had immense moral support at his back, yet moral support would not have sufficed to protect him from the king's anger. Nor would Gregory have ventured on so haughty a course, had he not had allies of another character. These allies were four in number, and require some description. First in importance come the Normans. For years bands of Norman warriors, pious folk, had passed through Southern Italy on their way to the Holy Land. Once a handful had helped a prince of Salerno to repel a Saracen attack. The prince, so the story goes, delighted with their valour, begged them to invite their compatriots to come. The invitation was readily accepted. Bands of gentlemen adventurers came, fought against Saracens, or Greeks, or the independent dukes and princes of Southern Italy, first as mercenaries in anybody's pay, and afterwards on their own account. They soon conquered a domain, and reached out in all directions. Some drove out the last Byzantines and acquired Southern Italy; some crossed to Sicily, performed prodigies of valour against the Saracens, and finally conquered the whole island (1060-90). In their raids northward they trespassed upon papal territory and came into collision with the Church. St. Peter's sword was drawn and brandished, but ineffectually. The Popes then concluded that martial deeds did not become them; and the Normans, on their part, were pious folk; so together they formed a happy solution. The Normans had possession of Southern Italy and Sicily, but merely by right of conquest; they were in the midst of an alien and far more numerous subject people, and wished for a legal title. The Popes, unable to acquire actual possession, did have, thanks to the _Donation of Constantine_, a legal title, derived, so they claimed, from the original source of legal titles, the Roman Empire. The mode of agreement was obvious; the Popes conferred Southern Italy and Sicily as feuds upon their liegemen the Norman chiefs, and they in return acknowledged the Popes as their lords suzerain. In this manner, "by the grace of God and St. Peter," the Normans founded the kingdom of the Two Sicilies, which for centuries after the Norman line died out continued to acknowledge the overlordship of the Papacy. The Normans were often disobedient vassals, but they knew that the Empire regarded them as robbers, and in the wars between Empire and Papacy remained loyal to their lords the Popes.