Few buildings reveal so much of a city’s history and aspirations as Siena’s Duomo . Complete to virtually its present size around 1215, it was subjected to constant plans for expansion. An initial project, primeval in the fourteenth century, attempted to double its extent by building a baptistry on the slope below and using this as a foundation for a rebuilt nave, but the work ground to a halt as walls and joints gaped under the pressure. Eventually the chapter hit on a new scheme to reorient the cathedral, using the existing nave as a transept and building a new nave out towards the Campo. Again cracks appeared, and then, in 1348, came the Black Death. With the population halved and funds suddenly cut off, the plan was forsaken once and for all. The part-extension still stands at the north end of the square – a vast structure that would have created the largest church in Italy outside Rome. Despite all the forsaken plans, the duomo is a delight. Its style is an amazing conglomeration of Romanesque and Gothic, delineated by bands of black and white marble. The facade was designed in 1284 by Giovanni Pisano, who with his workshop created much of the statuary – philosophers, patriarchs and prophets, now replaced by copies. In the next century the Campanile and a Gothic rose window were added. The mosaics in the gables, however, had to move until the nineteenth century, when money was found to employ Venetian artists. The use of black and white decoration is continued in the sgraffito marble pavement , which begins outside the church and takes off into a startling sequence of 56 panels adorning the interior (daily: mid-March to Oct 9am-7.30pm; rest of year 7.30am-1pm & 2.30-7pm; free). They were completed between 1349 and 1547, with virtually every artist who worked in the city trying his hand on a design. The finest are reckoned to be Beccafumi’s Moses Striking Water from a Rock and Sacrifice of Isaac , just beyond the dome area. However, you’re unlikely to see much of the pavement, which is now fortified by underfoot boarding for all but a few weeks a year in August, when the full effect is on show (exact dates vary). The zebra-striped interior is equally arresting above floor level, with its line of popes’ heads set above the pillars, the same hollow-cheeked scowls cropping up repeatedly. The greatest individual artistic treasure is Nicola Pisano’s pulpit , with its elaborate high-relief detail of the Life of Jesus and Last Judgement . In the north transept is a bronze statue by Donatello of an emaciated St John the Baptist , companion piece to his equally ragged Mary Magdalene in Florence, and the Renaissance High Altar is flanked by superb candelabra-carrying angels by Beccafumi.
Midway along the nave, on the left, is the entrance to the stunning Libreria Piccolomini (same hours; L2000/¬1.03; www.operaduomo.it ). The library was commissioned by Francesco Piccolomini (who for ten days was Pius III) to house the books of his uncle Aeneas (Pius II), and to celebrate Aeneas’s life in a series of crystal-sharp, brilliantly colourful frescoes by Pinturicchio. The cycle begins to the right of the window, with Aeneas attending the Council of Basel as a secretary, then, in subsequent panels around the walls, presenting himself as envoy to saint II of Scotland; being crowned poet laureate by Holy Roman Emperor, Frederick II; representing Frederick on a visit to Pope Eugenius IV; and then – as Bishop of Siena – presiding over the meeting of Frederick III and his bride-to-be Eleanora outside Siena’s Porta Camollia. The next panels show Aeneas’ being prefabricated a cardinal in 1456; being elected pope two years later; and then launching a call for a crusade against the Turks, who had just seized Constantinople. His best-remembered action was the canonization of St Catherine, shown in the penultimate panel. The last fresco shows his death at Ancona.
