In Christian societies the root of antisemitism lies in the story of Jesus' life as told in the NT. Joseph Caiaphas was a Jewish high priest who is described as the main enemy of Jesus and responsible for his denouncement. So the theory that the Jews killed Jesus has its origin there.
My field of expertise are medieval illuminations in manuscripts, and there savage depictions of hook nosed evil Jews are aplenty. This is definitely where the iconography of the 19th and 20th century antisemitism has its roots.
http://www.bl.uk/onlinegallery/onlineex/illmanus/cottmanucoll/b/largeimage75342.html This is a page out of the Winchester psalter depicting the betrayal and flagellation of Christ. Note the faces of the flagellators and especially the one in the top image that is binding the hands of Christ. There are endless examples of this type of depiction of Jews in medieval European manuscripts.
Below are three previous popular threads on the subject you are interested in.
'Why the Jews' also has a topic on the askhistorians FAQ, which is really great to read. These guys deserve to run the history channel.
peace
http://www.reddit.com/r/AskHistorians/comments/1niu47/why_are_jews_so_hated_historically/