in the public games of the Roman circus, was a napkin hung out at the praetor's or other great magistrate's seat, as a signal for the race or other diversions to begin. The mappa was received by the mapparius, or person who held it, from the consul, praetor, or other great officer. Notice was anciently given by sound of trumpet; but Nero is said to have introduced the mappa, by throwing his napkin out of the window to satisfy the people who grew noisy at the delay of the sports while he was at dinner.