Nothing in History occurs just because one person causes one event. Everything has to be understood in a wider context.
The European history, highly interconnected by nature, is a good example.
Far from a collection of unconnected happenings, Human history is a huge mesh of interrelated facts and concepts, which has been long understood in the context of Humanities taught in Universities.
History is mostly presented in a simplistic and localistic manner!
And this situation is not getting any better on todays’ reality as it is easier than ever before for anyone to find partial information about any issue.