The city walls of Florence were extended several times. Urban planning renewals were executed in the 13th and 14th centuries by Arnolfo di Cambio, Giotto and Andrea Pisano. The city wall was important not only for the purposes of defence, but also with regard to the Florentine tradition of commerce, which necessitated a clear division between rural and urban areas and good transportation routes. As a result, the construction of roads, bridges, city walls and customs posts at the most important city gates by well-known architects also progressed under Medici rule. Florence was the Italian capital from 1865 to 1871, which prompted the city to take down the walls, leaving only a few city gates which still exist today. On the south side of the River Arno, the old wall with the San Frediano, San Miniato, San Giorgio, Porta Romana and San Niccolò gates has been retained in good condition in its defensive character. The narrow alleys and steeply-climbing paths into the hills behind the city gates presented Hilde Lotz-Bauer with interesting photographic motifs.