Lo sviluppo sostenibile e la tutela della città storica. Il caso di Pienza.

In consequence of the Venice Chart definition of monument, following demographic changes and social develop-ments made necessary more adequate urban heritage conservation strategies. European Landscape Convention, UNESCO Recommendation on the Historic Urban Landscape, Italian National Landscape Chart, defined a wider concept of urban context, natural environment and their social, cultural and economic values with the intangible dimensions of heritage. The Pienza historic center is the result of a complex stratification process shaped by Pio II programs with the transformation of the medieval city. The following urban and architectural changes, the expan-sion of the contemporary city, the new economic development processes, mainly with commercial activities and tourism, need of a reflection and a balancing between the principle of sustainable development and the active con-servation and preservation of the existing resources of historical heritage.