What is the origins of Popes wearing a white soutane with other articles of clothing such as mozzetta in red?
Most sources say that the pope wears a white soutane since the time of Pope Pius V.
That is the traditional understanding of why the pope wears white. In fact, Pope Pius V simply continued to wear the habit under his papal robes, as a sign of familial affection to the Order, but also as a sign of humility: beneath the symbol of authority invested in the papal garb, he remained a humble friar.
According to another tradition, still quite widespread in 1700 and reported by Filippo Bonanni, in his work “Of Sacred Hierarchy” (Roma 1720), the use of the white robe for the popes derives from “the appearance of a white dove at the time of the martyrdom of St. Fabiano” ( L’Osservatore Romano July 14, 2010). - Why Is the Pope Always Dressed in White?
Yet another source claims the white soutane is linked to Pope Innocent V in 1276:
The first popes probably wore the common dress of their time, though increased power and prestige beginning in the time of Constantine caused that attire to become more regal in appearance. Later, like many clerics, they may also have worn academic gowns if they came from a university. Many of the liturgical and nonliturgical vestments used today have their origins in the everyday gowns and capes of earlier times, though some had political or academic symbolism attached to them.
It is believed that the white cassock became standard dress for the pope because of Innocent V, who was elected in 1276. He was a learned friar of the religious order founded by St. Dominic. As the first Dominican pope, he continued to wear the white habit of the order during his short pontificate. A professor of theology at the University of Paris, he was revered as an enlightened scholar and powerful preacher whose papacy sought peace and union with the Eastern Church. His renown must have affected his successors as it soon became common for the pope to appear in daily attire consisting of a white habit similar to the dress of the Dominican order. - Why does the pope wear white?
I am interest in a canonical answer that also reveals the origins of the symbolism of these two papal clothing colours.