#7 Romans combining their empire

The Romans combined their empire into one unit through military power, and roads. The saying "all roads lead to Rome" refers to the fact that the Roman empire had connecting roads which bridged all of the territories making up Rome together, and eventually led back to the city of Rome making the saying true for the Roman empire. These roads were laid down by slaves, however they were made possible by the Roman army. The Roman army would conquer and acquire slaves to make it possible to build the roads, then they would use the roads to conquer and transport things. It was the connecting roads, and the military power that know one wished to challenge that united Rome into one unit.