Geißelsäule
In the 1450s Piero della Francesca, in paintings such as "The Flagellation of Christ", demonstrated his mastery over linear perspective and also over the science of light. Another painting exists, a cityscape, by an unknown artist, perhaps Piero della Francesca, that demonstrates the sort of experiment that Brunelleschi had been making. From this time linear perspective was understood and regularly employed, such as by Perugino in his "Christ Giving the Keys to St. Peter" (1481–82) in the Sistine Chapel.