The Medieval Period of English literature is characterized by a shift from the medieval courts to the rural countryside, where the majority of the population lived. This change in setting and themes can be attributed to several historical factors that shaped the course of English literature during this period.

1. The Norman Conquest (1066): The Norman Conquest brought about significant changes in England's political and social landscape. It led to the establishment of a feudal system, which had a profound impact on literature. The new rulers, the Norman-French lords, introduced their own customs, traditions, and languages, which were reflected in literature. For example, the works of William Langland, such as "Dream of the Rood" and "Celtic Poetry and Romance," reflect the influence of French culture on English literature.
2. The Crusades (1095-1291): The Crusades, a series of military expeditions by European Christians to the Middle East, had a significant impact on English literature. They inspired tales of heroism, adventure, and religious devotion. Works like Geoffrey Chaucer's "The Canterbury Tales" and Dante Alighieri's "Divine Comedy" are examples of literary works that reflect the themes and motifs of the Crusades.
3. The Black Death (1347-1351): The Black Death was a devastating epidemic that killed millions of people across Europe, including many in England. This event had a profound impact on society, leading to increased anxiety about death and mortality. Literature during this period often dealt with these themes, reflecting the fear and uncertainty caused by the pandemic. Works like Thomas Malory's "Le Morte D'Arthur" and Sir Gawain and the Green Knight by Edmund Spenser also explore death and its consequences.
4. The Hundred Years' War (1337-1453): The Hundred Years' War was a long conflict between England and France that lasted for over a century. It had a significant impact on English literature, as it inspired stories of war, romance, and heroism. Works like Sir Philip Sidney's "Arcadia" and Edmund Spenser's "Aeneid" are examples of literary works that reflect the themes and motifs of the Hundred Years' War.
5. The Renaissance (14世纪末至17世纪初): The Renaissance marked a period of cultural and intellectual rebirth in Europe, including England. It saw the rise of humanism, an emphasis on individualism, reason, and classical learning. This period influenced English literature by introducing new ideas, styles, and techniques. Writers like William Shakespeare, who wrote during this time period, explored universal themes like love, jealousy, ambition, and power through his plays.

In summary, the Medieval Period of English literature was shaped by various historical factors, including the Norman Conquest, the Crusades, the Black Death, the Hundred Years' War, and the Renaissance. These events had a profound impact on literature, inspiring new themes, styles, and techniques that continue to shape English literature today.