Two horse bits
The two spiral horse bits, called moraglie (bits united to the reins), have an unusual appearance. Their stylized representation has made the definition and interpretation difficult for some time (they have often been generically described with the expression “twin spirals” (“spire gemelle”: Nardini, Le imprese, pp. 18-19). They are also identified by the definition of “horse bites”. The allegorical meaning is clearly connected to their use: they are an instrument of coercion used on horses, by loosening or holding back the reins. The allusion is to Federico, a man of government, whose power is illustrated by the motto that sometimes accompanies the emblem, belli fulgor et pacis auctor. Authority and command must be exercised with the proper balance of those who know how to be both a skilled leader and an artificer of peace, exercising political competence. It has been noted that the badge, adopted from Francesco Sforza, seems to be the allegory of Federico’s political program, as it seems to refer to the legacy of the politics of equilibrium of which the lord of Urbino wishes to consider himself a successor (see Lombardi, I simboli, p. 139; Fenucci, Notes, p. 84).
Urb. lat. 365, f. 106r - Urb. lat. 427, f. 2r
Likewise noteworthy is a certain complementarity of this symbol with that of the whisk broom, also inherited from Francesco Sforza, duke of Milan (d. 1466). The horse bits represent a tool of coercion used on horses, while the whisk broom is the symbol of the care of the tamer for docile and obedient horses (see Lombardi, I simboli, p. 139). The image of the horse bits is also found in the Studiolo (see Raggio, Lo Studiolo, p. 118, fig. 5-67).