The High Middle Ages are defined by the Crusades which started in 1095. These were military attempts by Western European Christians to regain control of the Middle Eastern Holy Land from the Muslims. Intellectual life was marked by the founding of Universities and the philosophy of reason gathered pace exemplified by Thomas Aquinas, the poetry of Dante and Chaucer, the travels of Marco Polo, and the architecture of Gothic cathedrals such as the astonishing achievements of Canterbury and Westminster. The High Middle ages is associated with advances in agriculture, increased crop yields therefore allowing a growth in the population of towns supported by rural food surpluses.
Late Middle Ages characterized by the Black Death and the de-population of towns and countryside. This led directly to the demise of the feudal system and a fundamental shift in the way society was organized. This period was ruled by a few rival dynasties, prevalent was the House of Plantagenet 1154–1399. This was a royal dynasty that came to prominence in the High Middle Ages and lasted until the end of the Late Middle Ages. Meanwhile the One Hundred Years War with France continued 1337–1453, immediately followed by the insular War of the Roses 1455–1485 where the House of York and Lancaster Battled it out for supremacy.