what date and year did the Holocaust begin and when did it end?
Different experts define the Holocaust in different ways. Some date its beginnings to the start of World War II. The first site below dates the Holocaust from the first day that Hitler became chancellor of Germany, January 30, 1933. It ended when Germany surrendered to the Allies, May 8, 1945.
http://www.jewishvirtuallibrary.org/jsource/Holocaust/history.html
http://www.ushmm.org/wlc/article.php?lang=en&ModuleId=10005143