It was in this Tuscan town that Renaissance town-planning concepts were first put into practice after Pope Pius II decided, in 1459, to transform the look of his birthplace. He chose the architect Bernardo Rossellino, who applied the principles of his mentor, Leon Battista Alberti. This new vision of urban space was realized in the superb square known as Piazza Pio II and the buildings around it: the Piccolomini Palace, the Borgia Palace and the cathedral with its pure Renaissance exterior and an interior in the late Gothic style of south German churches.
Criteria for inclusion as a World Heritage Site
|i||To represent a masterpiece of human creative genius.||All|
|ii||To exhibit an important interchange of human values, over a span of time or within a cultural area of the world, on developments in architecture or technology, monumental arts, town-planning or landscape design.||All|
|iv||To be an outstanding example of a type of building, architectural or technological ensemble or landscape which illustrates (a) significant stage(s) in human history.||All|
About the source: UNESCO
Within UNESCO's broad remit, this specialised agency of the UN works towards international cooperation agreements to secure the world's cultural and natural heritage, designating venues of exceptional value as World Heritage Sites.