The lantern is the adornment structure, usually octagonal, atop a cathedral dome. This element was also designed by Brunelleschi after a lengthy design competition. He was forced to "audition" for this portion of the dome due to running afoul of the wardens of the cathedral with his hot temper. It was completed in 1471. More: info.aia.org/aiarchitect/thisweek08/1024/1024p_duomo.cfm

AA243 Splendor.