Something I explained to my kids: a feud is in a sense the opposite of a war. In war the goal is to take territory and only incidentally to kill people. (If the enemy surrenders, so much the better.) Whereas in a feud the goal is to kill people rather than to take anything.
He's careful to qualify that statement with "For more than a century," implying that before that it wasn't. This is an eyeblink in the history of warfare. And it's only because troops had become disciplined. In preindustrial times battles were usually won when one side fled.
