The monumental squares built over a century and a half in the heart of Rome by Julius Caesar and the emperors Augustus, Vespasian, Nerva, and Trajan. These squares do not include the Roman Forum, the old Republican square, whose first layout dates back to the regal era (6th century BC). For centuries, it had been the political, religious, and economic center of the city, but it never achieved a unified character. Under Caesar and Augustus, the construction of the Basilica Julia and the renovation of the Basilica Aemilia, which marked the long sides of the square, gave the Forum a certain regularity.