The term Western worl, the West or the Occident (Latin: occidens -sunset, -west, as distinct from the Orient) can have multiple meanings dependent on its context (e.g., the time period, or the regional social situation). Accordingly, the basic definition of what constitutes “the West” varies, expanding and contracting over time, in relation to various historical circumstances. Some historians believe the West originated in the northern and eastern Mediterranean with ancient Greece and ancient Rome. While other historians such as Carroll Quigley's Evolution of Civilizations contend that Western Civilization was born around 400 AD, after the total collapse of the Western Roman Empire, leaving a vacuum for new ideas to flourish that were impossible in Classical societies. Over time, their associated empires grew first to the east and south conquering many older civilizations, and later to the north and west to include Central and Western Europe. Between the fall of the Western Roman Empire and the Renaissance, the West experienced a period of relative decline, known as the Middle ages, which included the Dark ages and the Crusades. The knowledge of the ancient Western world was preserved and survived during this period due to the concurrent ascendency of the Islamic Golden Age to the east and south. The term "first world" was also used, but not commonly.