In heraldry, the sun is a symbol of eternity, greatness and illustrious nobility. For this reason, over the centuries, its inclusion in the coats of arms of the oldest Italian families, with alternating acute or undulating rays, is always an expression power and ambition. These aspects come together in the figure of Gian Galeazzo Visconti, lord of Milan and founder of Veneranda Fabbrica del Duomo in 1387, the year in which he ordered Candoglia marble to be used for construction of the Cathedral recently undertaken by the Milanese, with the support of the archbishop Antonio da Saluzzo. For this purpose, on 24th October of the same year, Gian Galeazzo granted the Fabbrica use of the Candoglia quarries. But it was not an act of simple generosity: Gian Galeazzo also intended to make the new Cathedral a great monument to himself and his family, an expression of the Visconti power and the prime symbol of a city able to hold its own with the most important European centres.
The symbol of this ambitious project is certainly the famous “raza” (i.e. a radiant sun), present in the Duomo in the central window of the apse which houses the Window of the Apocalypse (no. 20), a symbol of the Viscontis when accompanied by the “biscione” (serpent): “la vipera che il milanese accampa” (the serpent that allows the Milanese to pitch their camp), as Dante wrote in the eighth canto of the Purgatory. The original project for the sculptural part of this window was approved by the Duke. However, the raza, the Visconti emblem, is symbolically interpreted in the window as “Sol Iustitiae”, i.e. the emblem of Christ, positioned below the representation of the Father and the Holy Spirit, more similar to an imperial eagle than to a dove.
With the light filtering through the large apse windows, to the east, in the direction of the rising sun, now, at the beginning of February, the great raza of the Duomo, with its splendid warm colours, attracts the attention of the faithful and visitors and is a prelude to spring.