Food / Origin of the pierogi [118]

I have always thought that pierogi was a polish food. Recently I looked into it and have found that many people attempt to take credit, including most european nations surrounding poland and of course the chinese want credit too. I think they refer to the tartars, mongolians who invaded poland around the 12th century I believe. Is the pierogi just thought of as a polish food. I have searched somewhat diligently in attempt to find the origin of this great and simple food. If anyone has any information I may have not found I would greatly appreciate.