Portrait of Cosimo I de'Medici

In January 1537 the ruler of Florence, Duke Alessandro de' Medici, was murdered by a cousin, and the city was suddenly without a head. The leading families settled on Cosimo, seventeen years old and from a side branch that had never governed. They expected a boy they could steer. Within months he had crushed a force of republican exiles at Montemurlo and begun a rule that lasted thirty-seven years. This portrait dates from that first year, before the polished images of Cosimo in armour that Bronzino and his workshop would later turn out by the dozen. It reached the Russian imperial collection in 1850, bought at the sale of a bankrupt Dutch king.