At around the start of the 20th century, the concept of "Western Civilization" as a means of understanding and teaching history was being developed. In part this was because of three main reasons.

• Growing international trade in an era of 19th century economic liberalism.
• Growing need to justify imperialism in which "Westerners" were seen as superior.
• European alliances and conflict--especially WWI--in which Europeans (and Americans) started to see themselves as having ancient historical bonds.

Thus, "Western Civ" came into existence and began being taught in universities and secondary schools. Prior to this, history education had been a mixed bag of classical and--for lack of a better word--ethnic/national studies. Sometimes western civ was called "world history" even though it was really just European history.

Then following WWII some people in America (at Colombia University) began to teach survey courses in regional global history in which students would study historical events on each continent. Some say this is because some Americans wanted students to know more about the world they were increasingly involved in. So regional global studies courses began to spread--although the narrative of "Western Civ" was still considered academically preeminent and more significant (and still is at the university level).

In the 1980s the current concept of "World History" came into existence in which continents are not studied separately but are examined together from a comparative perspective chronologically. So major themes and events during a period of time and what was happening in a variety of places during that time: what things make each place unique and what commonalities do they share? This model is the current consensus amongst those in the US like myself who specialize in World History (rather than those who just get "stuck" teaching it). Although many schools in the US—especially elitist schools--are still teaching Western Civilization courses and offer global education courses only as electives.