THE QUALITY OF THE DATA

The task of representing at one and the same time both Italy and the Middle Ages in this volume is a formidable one. All that I feel able to do for the history of family and household structure is to set out some of the preliminary results of a study of a fiscal doucment with the title catasto dating from 1427 and relating to Tuscany. This study was undertaken to determine the value of the catasto as a demographic source and to find out whether modern methods of treatment and analysis could be applied to these data without bringing about too many distortions.

David Herlihy of the University of Wisconsin was the first to suggest analysing the whole of this huge document with the aid of computers, and it turns out to be a splendid source, although it has to be handled with care. It is a document of remarkable fullness and precision to come from the early part of the fifteenth century, but one which is full of pitfalls because its nature reflects the requirements of taxation.

As for its size, there are nearly 360 volumes and bundles, shelved in the archives of Florence and of Pisa. The Florentine government decided in May 1427 to carry out a complete census of persons and of goods in the whole of the territory belonging to the city, that is to say from the sea to the Appenine Ridge.