Land was viewed as sacred, and it was bounded by posts and various kinds of markers, each of which was overseen and protected by various local pagan dieties.

Trespass upon the property or land of another individual or group (clan or tribe) was regarded as immoral, not just because the boundary was to be defended, but because it was a violation of the sanctity of the god or diety whose boundary was indicated.

There weren't any public places of record or notification.  A property owner simply told his neighbors where his land boundaries were.

In addition, owners may have used images of their household gods, rocks, marks on trees, hedges, and natural features such as streams, trees, lake shores, or ravines.

They made walls from stones, and finally built fences.  Members of some such early tribes are believed to have taken their children around the territory claimed by the tribe.  The children it is said were then spanked at the places where trails crossed into adjoining territories, impressing on young minds the ideas of non-trespass.

The ideas of private ownership, and prior to that the sanctity of tribal or clan rights to a territory, are deeply rooted in our history and experience.