To place sources in context, you should evaluate the reliability of the information you find. This may include examining the author's intent in producing the document as well as social or political bias in the work.
Primary sources, like modern writings, should be examined for objectivity on the part of the author or creator. It is important to recognize social conventions or presuppositions which may color an author's perception of an event. Here are some things to keep in mind as you explore these sources:
Did the author actually witness the event being described? If not, how did the author learn about the event? Were these sources reliable?
Did the events depicted actually happen? Are there enough details provided to enable you to verify the event using other sources?
Are there other accounts of the event? Do these accounts offer a different perspective or reach different conclusions?
Does the author's personal beliefs and preconceptions influence the account?
What is the purpose of the work? Is there evidence of political or social bias?
How does the author's perspective differ from that of a modern reader? How has society changed since the event? Does the passage of time affect the significance of the event?