North Italian School, circa 1640

The sitter is wearing the badge of the military order, Ordine del Redentore (or Order of the Redeemer), which shows two angels holding a reliquary containing drops of Christ's blood. The motto NIHIL ISTO TRISTE RECEPTO is inscribed around the edge. The order was instituted by Vincenzo I Gonzaga, Duke of Mantua (1562-1612), in 1608, and the number was restricted to twenty members. Vincenzo's intention was to rival the highly coveted chivalric Order of the Golden Fleece. It lasted for around one hundred years, until the Gonzaga family fell from power, and through this time comprised a total of one hundred noble knights, not only from Italy.

Other portraits of members of the Gonzaga family depict the sitters, such as Charles II Gonzaga, Duke of Mantua and Montferrat (1629065), likewise wearing the order.¹

¹ https://commons.wikimedia.org/wiki/File:Ritratto_di_Carlo_II_Gonzaga_Nevers.png