Francis Storr, 1911 Encyclopædia Britannica, Volume 8… (1911)
“ For our present purpose it is sufficient to observe the development of the idea of personal honour from which the modern duel directly sprang. In the ancient laws of the Swedes we find that if any man shall say to another, “You are not a man equal to other men,” or “You have not the heart of a man,” and the other shall reply, “I am a man as good as you,” they shall meet on the highway, and then follow the regulations for the combat. What is this but the modern challenge? By the law of the Lombards if one man call another arga, the insulted party might defy the other to mortal combat. ”
