«Recta linea et ad cordam». Measurements Tracing and Urban Practice in the Cities of Communal Italy 812th-13th centuries)

Abstract

The first decades of the 13th century mark a decisive turning point in the development of urban planning practices in the cities of central and northern Italy. The enhancement of municipal institutions enables the statement of technical and legal norms on which a substantial renewal of urban space is based. Soil measurement operations including its perimeter tracing are of paramount importance in this context. Used from the second half of the 12th century in order to control public places, these techniques derived from land surveying science and soon became customary also in the design of additions to city walls and new road structures as well as in the projects of extension and regularisation of public spaces. Systematic adoption of ropes stretched between pickets thus constitutes an incisive factor in the transformation of urban structure, under the sign of innovative rectilinear or polygonal geometries.

Numerous historical documents from main towns in central and northern Italy make it possible to analyse this particular topic during the 12th and the 13th centuries. They reveal that the improvement of technical tools and operational procedures affected the affirmation of new ‘urban planning’ methods and aesthetic concepts during the more mature period of the Communal Age.