These same tendencies also explain why offensive alliances are generally more fragile than defensive ones. Offensive alliances form in order to attack a specific target; once the victim is defeated, the motivation for the partnership is gone and quarrels over the division of the spoils are likely. Thus, Prussia's alliance with Italy in 1866 lasted only a few weeks, and members of the 1912 Balkan League of Bulgaria, Serbia and Greece fell upon each other within days of their victory over Turkey in May 1913. Similarly, the infamous 1939 Molotov-von Ribbentrop Pact that divided Poland between Nazi Germany and the soviet Union proved to be short-lived, and delayed Adolf Hitler's eastward advance for a mere two years.