Reminds me of the late Roman Empire.

Romans: Hey Germanic barbarians, if you join our military and defend us for a few decades, you and your families will receive citizenship and land to settle in!

Also the Romans after the Germans defend them for years: Soooooooooo about that whole land and citizenship thing…… How about we don’t do that, sorry guys….

The Germans: Bro we control the majority of your military. We are just going to take half your empire you little shits.