Question

Forgetting, i would even go so far as to say historical error, is a crucial factor in the creation of a nation, which is why progress in historical studies often constitutes a danger for [the principle] of nationality. indeed, historical enquiry brings to light deeds of violence which took place at the origin of all political formations, even of those whose consequences have been altogether beneficial. unity is always effected by means of brutality.

Answer 1

This is an excerpt from a lecture given in Paris in 1882
It is meant to spread the awareness that people in a certain nations tend to only willing to acknowledge the positive accomplishment of their countries.
And the authors argued that it is equally important to acknowledge the past shames so we could prevent it from happening again.