Crusader massacre chroniclers described blood flowing knee-deep as divine judgment on blasphemers.

Evidence

When he describes the massacre of Jerusalem’s inhabitants after its capture, it is as a glorious, if perhaps overzealous, revenge: … We came to the temple of Solomon [i.e., the Dome of the Rock], where they [the Saracens] used to sing their rites and festivals. But what happened there? If we speak the truth, we will be beyond belief. Suffice it to say that in the temple and porch of Solomon one rode in blood up to one’s knees, and up to the horses’ reins. This was truly a judgment [of God], that that place should receive their blood, since it endured for such a long time their blasphemies against God… . I say that this day saw the weakening of all paganism, the confirmation of Christianity, and the renovation of our faith. — John V. Tolan, Saracens, 647

Categorization

• CANDY: The ‘blood up to the horses’ reins’ hyperbole from a primary chronicle is a memorable, quotable image of medieval atrocity rhetoric.