This brilliantly structured and colourful painting depicts part of the battle of San Romano that was fought between Florence and Siena in 1432. The central figure is Niccolò da Mauruzi da Tolentino on his white charger, the leader of the victorious Florentine forces, who is identifiable by the motif of 'Knot of Solomon' on his banner.
This panel is one of a set of three showing incidents from the same battle. The other two are in the Louvre, Paris, and the Uffizi, Florence. This painting and its two companion panels were commissioned by the Bartolini Salimbeni family in Florence sometime between 1435 and 1460: only the Uffizi panel is signed. Lorenzo de' Medici so coveted them that he had them forcibly removed to the Medici palace.
The pictures may originally have had arched tops designed to fit below Gothic vaults. They were made into rectangular panels in the 15th century, possibly by Uccello himself. Uccello was much preoccupied with one point linear perspective, seen here in the foreshortening of shapes and arrangement of broken lances.
From The National Gallery Podcast: Episode Forty Nine, November 2010