Portrait of Christina of Lorraine, Grand Duchess of Tuscany

At a court breakfast in Pisa in December 1613, the grand duchess questioned the mathematician Benedetto Castelli, a former pupil of Galileo, about whether a moving earth could be squared with Scripture. Castelli wrote to Galileo about the conversation, and in 1615 Galileo answered her at length in what is still read as the Letter to the Grand Duchess Christina.

This portrait of her was painted in those same years, somewhere between about 1610 and 1615. Christina of Lorraine kneels in a widow's black, her husband Ferdinando I having died in 1609, at a prayer book open on a miniature of the Annunciation, the grand-ducal crown beside it. Through the opening behind her is a nondescript town on hills rather than Florence, which is how cataloguers tell this canvas from the other two versions of the composition kept in the city. The gallery credits Tiberio Titi, son of the painter Santi di Tito. Other scholars read it as workshop work and give the original to the version from the villa of Poggio Imperiale.