Short answers, pulled from the story.
The Order of the Golden Spur is a papal order of knighthood officially known also as the Order of the Golden Militia. It is conferred upon those who have rendered distinguished service in propagating the Catholic faith or who have contributed to the glory of the Church through feat of arms, writings, or other illustrious acts. In its modern form the honor is open to recipients regardless of noble birth.
The order is considered dormant because its last living member, Grand Duke Jean of Luxembourg, died on the 23rd of April 2019. With no living knights remaining, the order has no active membership.
Wolfgang Amadeus Mozart received the Order of the Golden Spur at the age of fourteen. In 1777 he sat for a portrait wearing the star-encircled cross of the order on his coat.
In the Papal Brief Quod Hominum Mentes of 1841, Pope Gregory XVI renamed the order the Order of Saint Sylvester and the Golden Militia, withdrew all existing faculties for conferring the honor, and banned any knight created by means other than a Papal Brief from using the title or decoration. He capped membership at 150 Commanders and 300 knights for the Papal States and appointed the Cardinal of Apostolic Briefs as Chancellor.
On the 7th of February 1905, Pope Pius X issued the motu proprio Multum ad excitandos, dividing the reformed order into two separate orders. One retained the name Order of St. Sylvester, while the other reclaimed the older name Order of the Golden Spur and was placed under the patronage of the Blessed Virgin Mary.
Recipients included the painter Titian, who was honored in 1533, the engraver Giovanni Battista Piranesi, and the classical composers Wolfgang Amadeus Mozart and Christoph Willibald Gluck. The violinist Nicolo Paganini and the adventurer Giacomo Casanova also held the decoration. Renaissance artists Raphael and Giorgio Vasari appear among the named recipients as well.