Your best option is to study as many sides of history as possible and formulate your own theories which will in turn be biased by your own environment, morals and values.
You will find most evil in history was based on good intentions, that the biggest lies ever propagated have been done so to benefit the wealthy and powerful.
Science tries to be a neutral ground for providing answers in regards to natural history, but is contaminated by the fact their is no control subject (neutral) upon which things can be compared.
Unfortunately with over a trillion lives lived and lost on this tiny blue marble, only a relatively small few stories have made it to today's 7 billion inhabitants.
We are lucky to have the freedom in our society to know there are two sides to every story, in some countries, and even some religions, the idea of there being a truth other then the one dictated causes anger, ridicule and may even result in imprisonment, torture and death.
Ignorance is not just not knowing about something, it can also be choosing to ignore the other side of the coin, being so trapped in the one dimension of your own vision that you believe their can be no other way to see it.
Even modern history which we have lived through is full of half truths dictated depending on which side of the aisle one sits, and you would hope that every one has the best intentions in mind when presenting, but truth will always be bent to better suit the audiences appetite to be right.
The things you like to read will generally be in agreement with your preformed ideals, and you will choose to disbelieve anything that does not conform to said ideals, but on the other side of the aisle the spectrum reverses.
There is a middle ground, a middle way, a path which lacks emotional attachment to what is right and wrong, however it also lacks the passion and pain that we associate with humanity.
The truth is. It exists, but it lay in cold hard facts devoid of opinion.
