Judensau (German for "Jews' sow" or "Jewish sow") is an image of Jews in obscene contact with a large sow (female pig), which in Judaism is an unclean animal, that appeared during the 13th century in Germany and some other European countries; its popularity lasted for over 600 years.
Read more about Judensau: Background and Images, Judensau in Wittenberg, Partial List, Image Gallery