In 1935, the Nuremberg Laws were passed that saw classification of German citizens by race. If all four of your grandparents were of German blood, then you were a good German. If three or four of them were Jewish, then you were Jewish. With one or two Jewish grandparents, you were considered a 'crossbreed'.
The laws prohibited marriage and intercourse between Jews and Germans, as well as the employment of German females under age 45 in Jewish households. They also stripped those of the non-German blood of their German citizenship.
Efforts to begin eliminating Jews from German society began even prior to World War II. Those of Jewish ancestry were slaughtered in mass killings and became the victims of 'pogroms' - systematic riots against and attacks on their population centers. The attacks included physical violence and murder against people, destruction of businesses, and destruction of their places of worship.
Beginning in September of 1941, all Jews living in the lands under German control were required to wear yellow patches on their clothing for identification. Jews were not permitted to become doctors, lawyers, or journalists, could not use state hospitals, and would not be schooled by the state beyond age 14.
By the time that 1942 rolled around, with WWII underway fully across the globe, one million Jews had already been killed by the Nazi regime. But this was only the beginning of the worst slaughter of one group of people in the history of mankind.
