Massacre at Ayyadieh

King Richard the Lionheart ordered 2,000 prisoners from the garrison of Acre and 1,000 women and children beheaded on the small hill of Ayyadieh in full view Salah ad-Din's army and his field headquarters on 20 August 1191.
King Richard had hoped to exchange the prisoners for the True Cross, 100,000 gold coins and 1,600 prisoners held by Salah ad-Din. Negotiations broke down and, convinced Salah ad-Din was stalling, Richard ordered the captives executed.
The massacre was controversial, even for Christians. Muslim chronicler Baha ad-Din noted many Crusaders disapproved of it.
In retaliation, Salah ad-Din sent the True Cross to Damascus and had 2,300 Christian prisoners in Damascus executed. More Christian prisoners were tortured and executed as word of the massacre spread around the Islamic world.