These two circular stained glass windows, depicting the Protomartyr Saints Stephen and Lawrence enthroned among angels within festooned frames, were made by the master glassmaker Nicolò di Piero Tedesco, on drawings by Lorenzo Ghiberti in 1412-1415, with reworkings, (perhaps commissioned by Ghiberti himself to update the style) in 1423 and 1432. These two works completed the decoration of the three stained-glass rosaces of the façade. The large Assumption of Mary in the center also had been created by Ghiberti and Niccolò di Piero Tedesco in 1405.

Ghiberti, famous as a sculptor for his monumental doors of the Baptistery, was actually born as a painter as he proved drawing this windows: and after these three in the counter facade he kept working on the cartoons of the stained glass windows in the presbytery area of the Cathedral for 40 years.

Ghiberti always maintained a uniform scheme, displaying the Saint in the centre, on an architectural throne, holding his own iconographic attributes. Ghiberti's style did not incorporate the innovations of Donatello's naturalism or Brunelleschi's perspective, and is still linked to the precious linearity of the contours, to the sought-after chromatic effect and refined detail, according to the late-Gothic manner.

Saints Stephen and Lawrence are depicted according to the sources that tell their stories, i.e. the Acts of the Apostles and the Golden Legend: they are young deacons (in fact they have the tonsure) and martyrs (they hold palms and Saint Stephen has on his head the stones of his lapidation). The thrones on which they stand, the angels who surround them and the beauty of their appearance and their clothes, together with the festoons of the frames allude to the eternal bliss of the celestial dimension which they received as a reward for the blood shed to be witnesses of the Gospel.

The decision to dedicate a stained glass window is also clarified with respect to their position: Saint Lawrence is above the portal that looks at the people of the basilica that bears his name, northwest of the Cathedral, and Stephen ideally "looks" at the people of the church named after him, from opposite side. In fact, with the same logic, in the same positions, these two saints were also depicted in sculptures on the medieval facade (today in the Louvre Museum).