Final answer:
In response to Viking raids that began in the late 8th century, medieval Europe adopted feudalism as a means of providing security. Lords granted land to warriors for military service, establishing a system based on land ownership and mutual obligations. This helped to stabilize regions during a time of frequent invasions and internal violence.
Step-by-step explanation:
The Viking raids that began in the late 8th century brought terror and destruction to Europe, particularly targeting monasteries and settlements for their riches. In response to the need for protection and security against these invasions, a new social structure known as feudalism emerged in medieval Europe. Lords sought to defend their territories and the people within them by granting land, or fiefs, to warriors in exchange for military service and allegiance, thus creating a network of mutual obligations centered around land ownership and defense.
The inaugural assault on unprotected Christian monasteries in the 790s heightened the European need for better defense systems. Fortifications were built, and Charlemagne expanded naval defenses to repel the Viking threat. As the Vikings began to settle in the lands they once raided, their integration into European society contributed to the shift from raiding to trading, with some becoming key figures in medieval commerce. The establishment of stable kingdoms in Scandinavia and the conversion to Christianity towards the end of the first millennium also helped reduce the frequency and scale of raids.
Feudalism became the dominant framework across post-Carolingian Europe as a mechanism to manage land and military service amidst a backdrop of continuous external threats and internal instability. This system of governance was instrumental in maintaining order and defending territories during a period marked by pervasive violence and the threat of invasions.