Lorenzetti, Ambrogio (lived 14th century)

Italian painter. His allegorical frescoes Good and Bad Government (1337–39; Town Hall, Siena) include a detailed panoramic landscape and a view of the city of Siena which shows an unusual mastery of spatial effects. He was the brother of Pietro Lorenzetti.

Equally important – though less well known – are his frescoes for the chapter house of San Francesco in Siena, which display a skill in the use of space and perspective which was very advanced for the period. The Presentation (Uffizi, Florence) is another authenticated work.