The opinion of the starting point of the simplified hard toil labor is in archaeology with "farming culture" from modification of the ancients' bone.

Occupation specialization invented the professional soldier.
In Europe, in order to acquire citizenship, the young slaves currently overworked by farming and materials handling operation in time of peace aimed at the soldier who risks his life.

In the change of generation, people left natural order. And it was going to find the way out in social order.

The social rank was invented by the place and sex of birth. The rank gave people the gap of knowledge.

In order to bury this blank, slaves took the post of military service. And the national strategy was able to be maintained because leaders admire this.

ё｛To be continue゛