. . . "In fact, the emergence of Florence, Lucca, Pisa, and Arezzo, and the evolution of the new city-states of Siena, Pistoia, Prato, and other towns such as San Gimignano, Volterra, Livorno, Colle val d'Elsa, and Grosseto is due to extensive trade.Nevertheless, throughout most of its history this whole area has been a prosperous region for agriculture and a central point for communication for road, sea" . .