Jack of Harts

I have visited the ruins of the people who lived on our worlds before we did. There are not many left, but they can be found if you look hard enough. Our government is not the only one who has tried to erase them from history. It can be seen in all of the ruins. They did not die out in the distant past. They were destroyed. They were defeated. They were wiped out. They were erased from history. Who hated them enough to want to erase the very memory of their existence from the universe? And what can we do about it now?