With the migrations and invasions occurring in the 4th and 5th centuries, trade routes across the Mediterranean were significantly disrupted. By the close of the 7th century, products from Africa had vanished from Western Europe, a situation acutely felt in regions like northern Gaul and Britain.

Christianity served as a vital link uniting Eastern and Western Europe, yet the Arab conquest of North Africa severed maritime ties between these areas. This eventually led to divergences in language, rituals, and liturgy between the Byzantine (Eastern) Church and the Western Church. While the Eastern Church utilized Greek, the West maintained Latin, leading to escalating theological and political disputes. By the 8th century, issues such as iconoclasm, clerical marriage, and state influence over the Church had created profound cultural and religious divides.

The East-West Schism formalized this division in 1054 when the papacy and the patriarchate of Constantinople mutually excommunicated each other over disputes regarding papal authority. This resulted in the establishment of the Roman Catholic Church in the West and the Eastern Orthodox Church in the East.

The division of monasticism also contributed to a political schism between Carolingian Europe and Byzantine Europe. The Carolingian dynasty, descendants of Charles Martel, seized control of the Gaul kingdoms of Austrasia and Neustria in a coup in 753. Charlemagne, known as Charles the Great, initiated systematic expansion that unified a large portion of Europe, ultimately encompassing modern-day France, northern Italy, and Saxony. His conquest of the Lombards in 774 liberated the papacy from threats of Lombard invasion, paving the way for the formation of the Papal States.

Charlemagne's coronation as emperor on Christmas Day in 800 marked a pivotal moment in medieval history, symbolizing the revival of the Western Roman Empire, as he ruled over territories once governed by Western emperors. This also diminished the perceived supremacy of the Byzantine Empire, as the Carolingians claimed imperial status, asserting their standing alongside the Byzantine realm. However, the new Carolingian Empire differed significantly from its predecessor, being primarily agrarian with few urban centers, as most inhabitants were peasants on small farms.

During the High Middle Ages, Europe's population surged from 35 million to 80 million between 1000 and 1347, driven by improved agricultural techniques, a decline in slavery, favorable climatic conditions, and the absence of invasions. Approximately 90 percent of this population remained rural peasants, many of whom formed small communities known as manors or villages, often under the authority of noble overlords, in a system referred to as manorialism.

While some peasants retained freedoms, the majority owed rents and services to their lords. The practice of assarting, or cultivating new lands by incentivizing peasant settlement, contributed to population growth. European society also included nobility, clergy, and townsmen. Nobles, whether titled or simply knights, exploited the manors and peasants under their control, granted rights to income through the feudal system.

By the 11th and 12th centuries, lands or fiefs became hereditary, primarily passing to the eldest son, contrasting with earlier practices of division among heirs. The nobility's dominance stemmed from land control, military service, castle defenses, and various tax immunities, enabling them to resist kings or other overlords.

The clergy comprised two groups: secular clergy, who lived among the populace, and regular clergy, often composed of monks living under strict religious rules. Townsmen, urban dwellers who did not belong to any village, did not fit neatly into the established societal categories. However, their numbers increased significantly in the 12th and 13th centuries as towns expanded and new population centers emerged.

Jewish communities found themselves largely confined to urban areas, barred from owning land or becoming peasants. Additionally, non-Christian groups, such as pagan Slavs in Eastern Europe and Muslims in Southern Europe, were present at society's periphery.

In medieval society, women were legally required to be subordinate to male relatives, though widows often retained more control over their lives. Nevertheless, women's roles were primarily domestic.

The early Middle Ages saw significant changes in Roman urban life and culture. Many Roman temples were repurposed as Christian churches, while city walls remained intact. In Northern Europe, cities experienced population declines.

Following the Roman Empire's conversion to Christianity, Jewish communities faced persecution and were pushed to settle in new regions. Judaism actively sought converts, with some Arab leaders even adopting the faith.

Zoroastrianism, a belief system centered on a dualistic view of good and evil, thrived in Persia and competed for followers against Christianity, particularly in the Arabian Peninsula. The emergence of Islam during Prophet Muhammad's lifetime (d. 632) brought these faiths into direct conflict.

After Muhammad's death, Islamic forces expanded rapidly, conquering much of the Eastern Roman Empire and Persia, beginning with Syria in 634-635, followed by Persia from 637 to 642, Egypt in 640-641, North Africa later in the 7th century, and the Iberian Peninsula in 711. By 714, much of this region, known as Al-Andalus, was under Islamic control, culminating in significant victories by the mid-8th century.

The Battle of Tours in 732 marked a turning point, with Muslim forces repelled by the Franks, leading to the decline of the Umayyad Caliphate, which was succeeded by the Abbasid Caliphate. The Abbasids relocated their capital to Baghdad and shifted focus towards the Middle East, losing control over various Muslim territories. Meanwhile, Umayyad descendants governed the Iberian Peninsula, the Aghlabids ruled North Africa, and the Tulunids took charge of Egypt.

By the mid-8th century, new trade routes were forming in the Mediterranean, with exchanges between the Franks and Arabs replacing the earlier Roman economic structures. The Franks traded timber, furs, weapons, and slaves in exchange for silk, spices, and precious metals from Arab lands.

In the 11th century, the Seljuk Turks expanded into the Middle East, conquering Persia in the 1040s, Armenia in the 1060s, and Jerusalem in 1070. In 1071, their army defeated the Byzantine forces at the Battle of Manzikert, capturing Emperor Romanus IV.

The Turkish invasion of Asia Minor significantly weakened the Byzantine Empire by displacing a large portion of its population and disrupting its economic core. The Turks later lost Jerusalem to the Fatimid dynasty in Egypt, while a resurgent Bulgaria emerged as a threat to Byzantine authority in the late 12th and 13th centuries.

Crusades were launched with the intent to reclaim Jerusalem from Muslim rule. The First Crusade was initiated by Pope Urban II at the Council of Clermont in 1095, responding to Byzantine Emperor Alexios I Komnenos's plea for assistance against Muslim incursions.

A massive mobilization of people from various social strata across Europe culminated in the capture of Jerusalem in 1099. Unfortunately, the crusades were also marked by violent pogroms against Jewish communities, particularly during the First Crusade, resulting in the destruction of Jewish populations in cities like Cologne, Mainz, and Worms.

Subsequent popes called for crusades in regions beyond the Holy Land, including Spain, southern France, and the Baltic. The Spanish crusades intertwined with the Reconquista, the campaign to reclaim Spain from Muslim control.