……la necesidad de reinventar una nueva arquitectura defensiva capaz de hacer frente al poder de la artillería se convirtió por este motivo en uno de los principales desafíos del Renacimiento italiano y tuvo como protagonistas a los principales arquitectos de su tiempo, que dedicaron gran parte de sus esfuerzos a encontrar una nueva forma de la fortificación efectiva, funcional y coherente…………el dibujo y la geometría se convirtieron en la principal herramienta para comprender las leyes de la artillería y en el principal método para guiar las reflexiones de los arquitectos durante el Renacimiento………la consolidación de este pensamiento geométrico forzó el paso de una idea de la fortificación basada en una idea de ‘resistencia por solidez de los materiales’ a otra fundamentada en el concepto de ‘resistencia por forma’……….el razonamiento geométrico descubierto por Leonardo y desarrollado por tantos otros arquitectos durante décadas se sintetizó en un conjunto de reglas geométricas que fundaron una nueva idea de la fortificación basado en la cualidad analítica del dibujo como medio por el que analizar y comprender la realidad…….el valor del dibujo como herramienta con la que guiar y definir la geometría fue parte esencial del proceso de refundación de una nueva lógica formal de la fortificación……………….
……..Vitruvio expresó con mucha claridad su modelo, pero no le acompañó de ningún diseño, lo que dejó abierto el campo para su interpretación posterior, convirtiéndose en una de las más fértiles fuentes de inspiración iconográfica para los teóricos de la ciudad del Renacimiento. Fueron ellos quienes se encargaron de traducirla a imágenes, interpretándola a través de una forma circular y una estructura radiocéntrica, compuesta de calles que partían de un eje central y se dirigían a las torres situadas en los vértices de los lados de su perímetro urbano, generalmente una muralla subdividida en una cantidad de lados que era siempre múltiplo de ocho. Así la mostraron en los inicios del siglo XVI autores como Cesare Cesariano (1521) o Fra Giocondo (1511) en sus traducciones, esta vez ya ilustradas, del texto vitruviano………
….in his Trattato d’architettura (1460), Filarete set out the attributes of his ideal city which he called Sforzinda….this city would be based on an eight-point, star-shaped plan within a circle and contain: three central piazze with a cathedral and ruler’s palace around the main piazza; a town hall in the centre of the second piazza with a treasury and prison around its edges; and a marketplace and headquarters for the chief of police in the third piazza…..instead of a grid-iron pattern of squares and streets, there would be eight radial avenues connecting the piazze with the gateways of the outer walls of the city…….the single most important driving force in the urban renewal of cities was the power and ideals of one man in power who was able to push for order in his particular city…….The preference of order and organization translated in the central role for geometric structures in urban plans, whether they be rectangular, circular, or polygonal, and in the desire for symmetry. Likewise, the human scale gained importance, which comes from the Humanistic approach where man is at the center of all things. Hence the idea of a city made for man, to his measure, and which meets his needs in every aspect……the Fortress town of Palmanova, founded in 1596 by the Venetians and one of the few ideal cities that was built from scratch and based on the study of a perfect model with radial symmetry, exemplifies the power that an urban design can have: the city was planned to be a perfect fortress: its shape was so threatening that nobody dared to attack it……….
……..Pienza, 1459-1462. Enea Silvio Piccolomini, pope with the name of Pius II, conceived with Leon Battista Alberti, who was developing new principles and rules in urban planning, the idea of transforming his native town of Corsignano into his and the court's temporary residence. Alberti suggested to the Pope to entrust the project and the direction of the works to the architect Bernardo Rossellino, who had already been his pupil at Palazzo Rucellai. The new vision of urban space based on Renaissance town planning concepts was established in the trapezoidal square, known as Piazza Pio II. The project included the construction or renovation of public and private buildings and the creation of shared spaces between them. Important new buildings were built around the square: the Cathedral, Palazzo Piccolomini, Palazzo Borgia (or Palazzo Vescovile), the Town Hall and the new buildings for cardinals accompanying the Pope, as well as 12 new social housing buildings near the wall and the Giglio Gate……..
……In 1492-94, on the Duke's initiative, a new square, the Piazza Ducale, was laid out in Vigevano, 12 km south-west of Milan. The work, which was carried out almost certainly to outline designs by Bramante, who was recorded there in 1492-96, involved the wholesale demolition of much of the old centre to create an open space extending more than 130 m from the façade of the cathedral - a size unprecedented in Lombardy - and the construction of new façades around three of the sides interrupted only at the dominant, towered entrance to the ducal castle towards the western end. Models for the scheme include the Piazza San Marco in Venice and the Renaissance Piazza della Loggia (c. 1485) in Brescia, as well as the ancient Forum Romanum as described by Vitruvius and Alberti, whose writings are echoed in an inscription on the castle tower……
