Six thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneouslySix thousand - year-old history arise spontaneously