ca. 1017

[Possible/Probable] Order of Pope Benedict VIII [Holy Roman Empire; Present-day Italy] 

Commentary from other sources:
1) Pope Benedict VIII has a number of Jews beheaded.

http://h-net.msu.edu/cgi-bin/logbrowse.pl?trx=vx&list=h-antisemitism&month=0605&week=&msg=CZNFZjiilGFJLVVjL6CxpQ&user=&pw=