History involves both primary and secondary resources. Primary resources include things such as diaries, receipts, tickets, pictures, clothing, personal recounts and artifacts.
Primary evidence can be subjective and can be something like a first hand report.
A historian is required to be objective, impartial, detailed, comprehensive, detached, and scholarly. Yet they can never be completely impartial since it is their own biases which gives interest to what one is reading. History is a matter of interpretation of past events and records by historians who make history come together and come alive. Historical facts are events that really occurred and have no life or meaning on their own. Historical facts need to be brought to life in history books or they will simply vanish as did many oral histories.