Cut into the stonework of the imposing Palazzo Salimbeni is a name that has been entwined with the fortunes of this Tuscan city for five centuries: Monte dei Paschi, or Mount of the Pastures.

Since the days of the Medici family in Florence, 40 miles to the north, the banking house of Monte dei Paschi has rained wealth on the people of Siena. For 541 years, it has endured war, plague and panic, and it stands today as the world’s oldest operating bank.