Having gained control of Verona, Rome's rulers decided to fortify the city so as to consolidate the Alpine border and create a bridgehead for possible future military ventures.

[3] A new center was therefore founded on the other bank of the Adige River, where its wide bends formed a kind of natural peninsula, a valid defense against possible attacks.

[4] The curtain wall was provided with two main gates, Porta Iovia (now called Borsari) along the decumanus maximus and Porta Leoni on the cardinalus maximus, as well as a series of towers placed at the decumanus and minor cardinus that acted as posterns: some of them were provided with a passage for chariots in the center of the street and two smaller side passages for pedestrians, at the sidewalks.

[6] A second important moment was experienced by the city around the middle of the third century, when it found itself at the center of a clash between the legitimate emperor, Philip the Arab, and his rival, Decius.

[10][11] The work lasted only seven months, from April 3 to December 4, 265: the remarkable speed with which the new curtain wall was built is revealed by the extensive use of bare materials in a rather haphazard masonry.

The suburban neighborhoods that had developed between the republican curtain wall and the natural depression of the Adigetto, thus outside the more consolidated fabric, remained excluded from the defensive system because they were too extensive and difficult to defend.

Through these interventions Gallienus succeeded in endowing Verona with once again harmonious and effective defenses, suitable for controlling both river traffic and the route of the Adige valley, from where the danger of aggression was greater.

[9] Moreover, Theodoric could also be credited with the building, or at least the reconstruction, of the city walls around the hill of San Pietro on the left side of the Adige River.

Among the clues that would point to his commissioning would be both written and material sources: the former can be traced in the Iconografia rateriana, a 10th-century map depicting Verona, in which the Republican-era curtain wall and the one surrounding the amphitheater are depicted in a bright green color, while the outermost curtain wall to the right of the Adige and the hillside are in a pinkish color, thus lending greater credibility to the hypothesis that the latter two are contemporary.

[19] Thus, the two segments both started from the bank of the Adige and continued in a northwest-southeast and northeast-southwest direction, respectively, in keeping with the orientation of the urban layout of Roman Verona.

This section was 7.5 meters high, thus maintaining the same height as the previous one,[11] however, on this occasion extensive use was made of rubble blocks probably from necropolises, street pavements and public buildings.

[25] In addition, there was a possible construction of an appendage of the walls also on the left bank of the Adige, which allowed for protection from possible attacks from the north of both the Roman theater of Verona and the Pietra and Postumio bridges.

However, it has been hypothesized that they ascended along the ridge of the monumental hill, included the peak on which a temple stood, then descended downstream from the shoulder of the pons marmoreum, rejoining the riverbank.

[13] The plugging and final closure of the posterns and pedestrian gates on either side of the defensive towers dates back to later Gallienian times;[26] Theodoric the Great was responsible for the building of a new curtain wall that slavishly traced the course of the previous defense: this remained about ten meters further inland and continued to maintain its military function, making a system with the new Theodoric walls, which were almost twice as high as the Roman ones, no less than 13.65 meters.

[27][28] Most likely, the city wall erected in the imperial age on the slopes of St. Peter's Hill was strengthened or rebuilt, because of its eminent and strategic position, so much so that it was on the left side of the Adige that the king had his residence built, perhaps renovating the structures of the Roman odeon.