Different scholars have different theories of history, so the response to this question might depend on who answers you. As a general rule, you want to consider when events take place, few people are thinking that history is taking place.

When events take place, there are, as I said, several perspectives that may be taken. Some people believe that events are driven by leaders, and without particular leaders in particular times and places, those events would not take place. Some people have a geographical perspective, and argue that events take place because of factors such as climate and topography and location.  For example, events that happen on an island are not likely to happen in the same way on the mainland, or that events in a very warm climate happen in a way that is different from events in a very cold climate. Some historians see historical events through the prism of ordinary people, saying that events are just an accumulation of ordinary day-to-day decisions of the people all around us.  Still other experts view history through an economic lens.  They see history as driven by economic decisions, money, greed, poverty, etc.  I would have to say that each of these perspectives is important, and that you will have to decide whether you want to view history through the eyes of one discipline or through the eyes of many disciplines. 

Good luck to you.