The urban expansion will now be projected, with geometric criteria. The paradigmatic case will be that of the Addizione Erculea of ​​Ferrara, an extension of 1492 commissioned by Hercules I of Este from Biagio Rossetti. In this expansion, an axis is drawn towards one of the gates of the new extension (Corso Ercole I d'Este"), leaving the other two gates joined by another axis (Corso Biagio Rossetti"). At the crossroads of both, the "Quadrivio degli Angeli", three palaces are located: Palace of the Diamonds, Palazzo Prosperi Sacrati) and Palazzo Turchi di Bagno). The cross divides the city into four quadrants, in which it inscribes a grid, in which the other singular elements and the important square, Piazza Ariostea, will be introduced. To break the continuity of the building, parks are inserted in the plot. The Este Castle becomes the new center of the city.

Palermo will also be the subject of an urban remodeling, by introducing a large cross of streets on the medieval fabric, the current Vittorio Emanuele "Via Vittorio Emanuele (Palermo)") and Maqueda "Via Maqueda (Palermo)"), forming the Quattro Canti square.

Other expansions will be carried out in bastioned areas: the expansion of Livorno (century ) is an example of a reticular extension project, with a square central plaza and two large axes. A façade ordinance is established, according to which all the homes facing the square have a porticoed ground floor, first, second and undercover"), and a statue is located on the wall visible from the sea, the monument to Ferdinand I, which becomes the perspective focus of the street.

In 1608 Charles de Gonzaga founded Charleville, with a central square and secondary squares around it. The main square is dominated by the ducal palace. The four large streets that lead to the gates divide the city into four neighborhoods, united by the square. Each neighborhood has its own church. Residential buildings are subject to a façade ordinance: brick on the panel, stone for the arches "Arch (architecture)"), slate for the roofs "Roof (construction)"), ground floors with open arches plus two upper floors, and individual roofs. The square of this city will be the precedent of the first royal square in Europe: the Royal Square in Paris, which will be a model for all the royal squares in France until the 20th century.

The treatise of the time will already carry out classifications of the cities that were being built:

"The governments of the Renaissance (the manors, which replace the communal governments and national monarchies) do not have the political stability or the sufficient means of financing to act in long and committed programs. The artists work individually and lose contact with the collective organizations that ensured the continuity of construction workers and medieval urban planning.

In this way, Renaissance architecture carries out its ideal of proportion and regularity in some isolated buildings but is not capable of founding or transforming a city.

"Literaries and painters describe and paint the new city that cannot be built, remaining as a theoretical objective, as the ideal city."

Despite the development of Utopias, the only ideal cities that will materialize will be anti-utopias: ideal defensive cities, as opposed to utopias, which are attempts to create an egalitarian and intellectual city. Thus, there will be a series of works carried out by military engineers, which will focus on defensive aspects, especially the wall, which will occupy an area sometimes larger than the city itself. They are projected from exterior to interior, starting the project with the wall.

Examples of military towns of the time could be Zamosc (Poland), Valletta (Malta) or Rosas "Rosas (Gerona)") (Spain), although the clearest example is the city of Palmanova "Palmanova (Italy)"), designed by Vincenzo Scamozzi in 1593. He includes it in his work "L'idea dell'Architettura Universale". Fortified, it aims to be a defensive city within the Republic of Venice. It is a nine-sided polygon with three doors, in the center of which there is a hexagonal square from which six streets radiate. Three rings of streets surround the central square. Around the central square there are secondary, commercial squares.

It will be the culmination of Renaissance urban planning and perspective, the creation of a great capital for the Papal States and for the Catholic Church, by Domenico Fontana and Pope Sixtus V.

The aim is to create a new urban order using the elements of the Renaissance perspective, from the layout of large straight lines over the fabric of the medieval city, connecting the strong points, the seven great pilgrimage churches: San Pedro del Vaticano, Santa María Maggiore, San Lorenzo Outside the Walls, San Juan de Letrán, Santa Cruz de Jerusalem, San Pablo Outside the Walls and San Sebastian. The new urban center will be St. Peter's Basilica, and the subcenters will be the other large basilicas. To unite them, streets of enormous dimensions will be opened, and the urban fabric will be organized with other streets and squares.

After the Western Schism, the popes had abandoned Rome. The papacy will be restored when Martin V settles definitively in Rome in 1420. Then the urban planning actions will begin on the now capital of Christianity. In 1425, Martin V reformed the position of the road masters and placed them at the service of the popes to rectify streets and open new ones. Nicholas V, between 1447 and 1455, proposed a program of actions that would provide a fortress (Castle Sant'Angelo), a palace (the Apostolic Palace) as the seat of papal power, and a church (St. Peter's Basilica, then designed by Alberti). This pope will build his own city on the Vatican hill, the city of the Curia, with a residential area, administration and government. The main points of the organization of this city will be:.

Each pope will open a new street in Rome, either by straightening an existing route (Via Pettinari"), recovering a disused route (Via Lungara) or opening them ex novo") (Via Lungaretta"), Via dei Banchi"). The urban fabric becomes more complex, with intersections of streets in a cross (Quattro Fontane), a trident (Piazza del Popolo), a star... all on a city scale, with perspective limits that reach 4 km in length.

The premises of the urbanization process will be three:[2]​.

The new planning, proposed by Sixtus V, had three priority objectives. Repopulate the hills of Rome by providing continuous water supply; create an aesthetic city that would overcome the frequent configuration of streets and public spaces as a result of the aggregation of disparate buildings and integrate into a single system of main streets the works carried out by their predecessors, linking key points of the city.

The urban expansion will now be projected, with geometric criteria. The paradigmatic case will be that of the Addizione Erculea of ​​Ferrara, an extension of 1492 commissioned by Hercules I of Este from Biagio Rossetti. In this expansion, an axis is drawn towards one of the gates of the new extension (Corso Ercole I d'Este"), leaving the other two gates joined by another axis (Corso Biagio Rossetti"). At the crossroads of both, the "Quadrivio degli Angeli", three palaces are located: Palace of the Diamonds, Palazzo Prosperi Sacrati) and Palazzo Turchi di Bagno). The cross divides the city into four quadrants, in which it inscribes a grid, in which the other singular elements and the important square, Piazza Ariostea, will be introduced. To break the continuity of the building, parks are inserted in the plot. The Este Castle becomes the new center of the city.

Palermo will also be the subject of an urban remodeling, by introducing a large cross of streets on the medieval fabric, the current Vittorio Emanuele "Via Vittorio Emanuele (Palermo)") and Maqueda "Via Maqueda (Palermo)"), forming the Quattro Canti square.

Other expansions will be carried out in bastioned areas: the expansion of Livorno (century ) is an example of a reticular extension project, with a square central plaza and two large axes. A façade ordinance is established, according to which all the homes facing the square have a porticoed ground floor, first, second and undercover"), and a statue is located on the wall visible from the sea, the monument to Ferdinand I, which becomes the perspective focus of the street.

In 1608 Charles de Gonzaga founded Charleville, with a central square and secondary squares around it. The main square is dominated by the ducal palace. The four large streets that lead to the gates divide the city into four neighborhoods, united by the square. Each neighborhood has its own church. Residential buildings are subject to a façade ordinance: brick on the panel, stone for the arches "Arch (architecture)"), slate for the roofs "Roof (construction)"), ground floors with open arches plus two upper floors, and individual roofs. The square of this city will be the precedent of the first royal square in Europe: the Royal Square in Paris, which will be a model for all the royal squares in France until the 20th century.

The treatise of the time will already carry out classifications of the cities that were being built:

"The governments of the Renaissance (the manors, which replace the communal governments and national monarchies) do not have the political stability or the sufficient means of financing to act in long and committed programs. The artists work individually and lose contact with the collective organizations that ensured the continuity of construction workers and medieval urban planning.

In this way, Renaissance architecture carries out its ideal of proportion and regularity in some isolated buildings but is not capable of founding or transforming a city.

"Literaries and painters describe and paint the new city that cannot be built, remaining as a theoretical objective, as the ideal city."

Despite the development of Utopias, the only ideal cities that will materialize will be anti-utopias: ideal defensive cities, as opposed to utopias, which are attempts to create an egalitarian and intellectual city. Thus, there will be a series of works carried out by military engineers, which will focus on defensive aspects, especially the wall, which will occupy an area sometimes larger than the city itself. They are projected from exterior to interior, starting the project with the wall.

Examples of military towns of the time could be Zamosc (Poland), Valletta (Malta) or Rosas "Rosas (Gerona)") (Spain), although the clearest example is the city of Palmanova "Palmanova (Italy)"), designed by Vincenzo Scamozzi in 1593. He includes it in his work "L'idea dell'Architettura Universale". Fortified, it aims to be a defensive city within the Republic of Venice. It is a nine-sided polygon with three doors, in the center of which there is a hexagonal square from which six streets radiate. Three rings of streets surround the central square. Around the central square there are secondary, commercial squares.

It will be the culmination of Renaissance urban planning and perspective, the creation of a great capital for the Papal States and for the Catholic Church, by Domenico Fontana and Pope Sixtus V.

The aim is to create a new urban order using the elements of the Renaissance perspective, from the layout of large straight lines over the fabric of the medieval city, connecting the strong points, the seven great pilgrimage churches: San Pedro del Vaticano, Santa María Maggiore, San Lorenzo Outside the Walls, San Juan de Letrán, Santa Cruz de Jerusalem, San Pablo Outside the Walls and San Sebastian. The new urban center will be St. Peter's Basilica, and the subcenters will be the other large basilicas. To unite them, streets of enormous dimensions will be opened, and the urban fabric will be organized with other streets and squares.

After the Western Schism, the popes had abandoned Rome. The papacy will be restored when Martin V settles definitively in Rome in 1420. Then the urban planning actions will begin on the now capital of Christianity. In 1425, Martin V reformed the position of the road masters and placed them at the service of the popes to rectify streets and open new ones. Nicholas V, between 1447 and 1455, proposed a program of actions that would provide a fortress (Castle Sant'Angelo), a palace (the Apostolic Palace) as the seat of papal power, and a church (St. Peter's Basilica, then designed by Alberti). This pope will build his own city on the Vatican hill, the city of the Curia, with a residential area, administration and government. The main points of the organization of this city will be:.

Each pope will open a new street in Rome, either by straightening an existing route (Via Pettinari"), recovering a disused route (Via Lungara) or opening them ex novo") (Via Lungaretta"), Via dei Banchi"). The urban fabric becomes more complex, with intersections of streets in a cross (Quattro Fontane), a trident (Piazza del Popolo), a star... all on a city scale, with perspective limits that reach 4 km in length.

The premises of the urbanization process will be three:[2]​.

The new planning, proposed by Sixtus V, had three priority objectives. Repopulate the hills of Rome by providing continuous water supply; create an aesthetic city that would overcome the frequent configuration of streets and public spaces as a result of the aggregation of disparate buildings and integrate into a single system of main streets the works carried out by their predecessors, linking key points of the city.