How to protect your house with doors from the company outpost

A man about the protection from not past guests of his home has been thinking for a long time. And his very first attempts to themselves, and to secure their family formed the basis of modern etiquette, establishing the outpost of the door. Although it is just about tradition when a man passes the first to the room. Of course, in the Stone Age he checked so the absence of warriors from someone else’s tribe or wild animals in his dwelling.