Most people at the time were Christian. Christianity brought everyone together in the spiritual community.
Piety
Around 1000 A.D. piety greatly increased. the definition of Piety: An individuals devoting to their designated religion.
Pope Leo IX
In the 900's and 1000's popes had little authority until 1049, Pope Leo IX came to power. Leo believed Europe's clergy had become corrupt. One of Leo's biggest concerns was Simony, the buying and selling of church officials.
Excommunicated
Kings and Bishops did not think Leo should have that much power. One person who rejected Leo's authority was the patriarch of Constantinople. The Pope excommunicated him and the Christian Church split in two. Those who sided with Leo were Roman Catholics and those who sided with the Patriarch of Constantinople were Orthodox.
Pope Gregory VII
The Pope gained political power. The Papal States in Italy were ruled by the Pope. Pope Gregory VII and the Holy Roman emperor Henry VI fought over who had the power to hire Bishops. Their argument outlived them both and later popes and emperors compromised, saying that local clergy would choose bishops, but their choices could be vetoes by secular rulers.
Monasticism
In the early 900's a small group of monks wanted to return monasticism to its strict roots. They established a monastery at Cluny, France where they lived strictly according to the Benedictive Rule. This monastery became very influential, and such other monasteries popped up, some more strict than others.