Hi JScones,
got something for you: the "Molotov-Ribbentrop Pact" (non-aggression-pact between germany and the Sovjet Union "Deutsch-Sowjetischer Nichangriffspakt"). For details see
http://en.wikipedia.org/wiki/Molotov-Ribbentrop_Pact
This was the "Start-Sign" for the invasion of Poland.
Greets
rowi58