Liber de scacchis (translation into Venetian dialect).

The rooks whiche ben vicaires and legats of the kynge ought to be made lyke a knight upon an hors and a mantell and hood furryd with menevyer holdynge a staff in his hande & for as moche as a kyng may not be in alle places of his royaume Therfore the auctorite of hym is gyven to the rooks whiche represent the kynge.