How did this rivalry start between Footba

Im not talking about teams, im talking about the 2 actual sports between american football and soccer (real football)? People keep fighting back and forth between which sport is better or tougher and people like to bash the other sport. Would you consider this a rivalry? Same thing with American football vs Rugby (pads and armor vs tough real fighting without any protection) and baseball vs cricket. People like to invade sections and trash talk the other sport! When did these rivalries start?