Stein Aage,
I don't want to turn this discussion into a college lecture, but you have some very wrong ideas about History as an academic discipline.
The ideas you are talking about belong to a field called Historiography. Basically, Historiography is the "history of history". It deals with the different ways throughout history that people have understood what history means, as well as how to research and write about it, and what is important and what isn't.
You think History is a science. That is an idea from 150 years ago, when historians thought the academic study of History could be "modernized" so History would have the firm foundation that sciences like biology and chemistry have.
Even 100 years ago it was becoming clear that History is not a science in the same way biology and chemistry are.
History has an epistemological limitation the other sciences do not. The word "epistemology" means what we know, how we know it, and the limitations on our human knowledge.
Unlike other scientists, Historians cannot define their field by using the scientific method of verifiable and repeatable empirical testing of hypotheses. For example, they cannot repeat historical events to see if they turn out the same way. They are limited to analyzing what is already written and what can be inferred from those writings and from other data.
Historians also have to recognize that written texts are an imperfect source. None of them can ever tell the whole story. Further, other texts might not have survived, and the texts that have survived might be biased and might have been falsified.
In other words, the data gathered and used by historians is not at all like the data gathered and used by the sciences.
So then, your idea of theories and hypotheses is fundamentally irrelevant. Modern historiography is primarily narrative and analytical rather than experimental ("scientific"). When an historian writes about their research and conclusions they are entering a dialog with other historians. They are not announcing a final truth.
The dialog occurs over long periods of time. Those other historians might accept or reject (or ignore) the analysis. In many ways, modern historians is like a jury in a court of law. That's why you see so often see someone say "the majority opinion is this" or "a strong minority believe that".