The following outline is intended as to provide one example of how to write an essay.
Of course, exactly what constitutes 'the evidence' is almost invariably one of the issues under discussion among the historians who are most deeply engaged with the problem, but in general for each historical question there will be a body of evidence which is recognised as being relevant to it.
This body of evidence will typically comprise what the primary sources tell us about the events and phenomena under discussion.
We want you to show us that not only have you acquired a knowledge of the topic but also that you fully understand the topic and the issues raised by it.
Essays test understanding by asking you to select and re-organise relevant material in order to produce your own answer to the set question.
You will never be asked to produce a narrative of what happened.
In rare circumstances, a few sentences of narrative may form part of the evidence cited in support of a point, but the essay as a whole should be organised according to a logical structure in which each paragraph functions as a premise in the argument.
'To-what-extent' questions involve a judgement of measure.
One way of answering the question would be set up a series of 'tests', as it were, that can be investigated in turn.
Essential steps: select a question; identify the subject of the question; what are you being asked to do - that is, what kind of information will you need to answer the question, and how will you have to treat it?
Circling the key words in the question is sometimes a helpful first step in working out exactly what you need to do.