Annunciation, 1344 Lorenzetti's final piece, telling the story of the Virgin Mary receiving the news from the Angel about the coming of baby Jesus, contains the first use of clear linear perspective. Though it is not perfect, and the gold background that is traditional for the time renders a flat feeling, the diagonals created on the floor do create depth. [https://en.wikipedia.org/wiki/Ambrogio_Lorenzetti]