I certainly hope you're not ignoring Christians attacking each other also.
"During the Middle Ages, European kings and popes continued the practice of compelling Jews to wear distinguishable clothing or markings.
On November 11, 1215, in Rome, Pope Innocent III convened the Fourth Lateran Council. It was one of the largest ecumenical councils ever to assemble. The Council decreed that Jews and Muslims were to wear identifying markers or clothing at all times that made them readily distinguishable from Christians. It was the last stage in a series of measures by the Church to inhibit social contact between Jews and Christians. Issued as Canon 68, the decree became the basis of the subsequent imposition of a so-called Jewish badge in Christian kingdoms.
The Papal order was most successfully enforced in England, where, in 1217, King Henry III ordered male Jews to wear a badge on the front of their outer garments. In 1275, King Edward I specified the color of the badge and its size. Jews over the age of seven were required to wear a piece of yellow taffeta, six fingers long and three broad, over the left chest of the outer garment."
https://www.ushmm.org/wlc/en/article.php?ModuleId=10008212