In chapter 55, a gentleman from Lombardy, the squire Galias of Mantua enters the story, wishing to perform a deed of arms. He was, the author believes, the same Galias of Mantua who later, as a renowned knight, fought against Jean le Maingre, (called Boucicaut) Marshal of France before the Lord of Padua. This was the son of the elder Boucicaut who is portrayed as Jehan's friend in the romance.
Now, Fiore dei Liberi, master of arms, writing in the early 15th c., records among his students Sir Galeaz or Galeaco of Mantua, who fought against the French knight Bucichardo, and the combat is also recorded as occurring in 1395 in the Cronaca carrarese.
So de la Sale wove the historical Galeaz of Mantua into his fictional work to give it greater verisimilitude, and was careful enough about the chronology to present his Galias as a squire rather than the renowned knight he would be when he fought at Padua.