 Complete the following phrase:  He married the sister of a fellow historian, and later ghetto chronicler, Emanuel Ringelblum. After the Nazi invasion of Poland on 1 September 1939 Artur, along with his wife and child, escaped to his wifes hometown in the east, the small town of Buczacz now Buchach, Ukraine. However, as a consequence of the Nazi-Soviet pact known as the Molotov-Ribbentrop Treaty, on 17 September the Soviet Union also invaded Poland and Buczacz fell within the 