INTRODUCTION TO SOCIOLOGY 785
a center, a differentiation between the frontier properly so called and this center should take place. This differentiation was, at the same time, economic, religious, and political.
Thereupon Romulus drew a furrow in order to designate the circumference of the city, as the head of a family left a strip of ground uncultivated around his domain. He did this by striding around with his head veiled, priestly garments covering him. He is the chief of the city and its pontifex, as the head of the family in the chief of his community. He also holds the handle of the plow and chants his prayers, followed by his companions. The clods raised by the plowshare are carefully thrown to the inner side of the circumference, in order that no portion of the land may belong to an outsider, and also in order to prepare a new obstacle at the side of the trench. Indeed, if the soil dug out is called the fosse, the earth cast inside is called the moat or wall.
The ceremony as performed by Romulus was similar to the Etruscan ceremony etrusco ritu; perhaps it was an imitation. But then one would have to admit that the founders of Rome were Etruscans. In sociology a law governs imitation : the same social conditions produce naturally analogous institutions and creeds.
After the outline of the city has once been established, it con- stitutes the frontier, as the ancient city is a closed city and as, in this respect, it is connected with the primitive community which also constitutes a closed mundus. This sacred frontier is invi- olable ; it is forbidden to transgress it, for this means to go into a foreign land, to the enemy. Remus had to pay for his sacrilegious infraction with his life, but he proved at the same time that each frontier is destined to be crossed.
No line surrounding a city is absolutely closed or uninter- rupted. The legendary founder of the city of Rome lifts the plow at certain places ; he carries it portat. The gates, portae, are the places where Romulus has interrupted the trench and the wall, where he has carried the plow.
It should be noticed now that here, as in the strip left untilled between the family estates, we see' something reappear and develop which in the case of states of more considerable size will become the march, the territorial border. The pomocrium is the sacred
