To explain this, Charles Martel was the grandfather of Charlemagne and he stopped the invasion of Francia (today's France basically) by the Muslims. They never tried again. Another hero in this ongoing WAR were the Eastern Orthodox Christinas of Constaninople who prevented the Muslims from invading the Balkans and Russia.
We do need, especially here in the US, an El Cid, a Martel, a Richard the 3rd, etc.
I think you meant Richard I. Richard III was the one who murdered his nephews in the tower. Richard II was the one who got all of his nobles to overthrow him. Richard I went on Crusade.
Don’t forget Vlad Tepes.