The Mule used for Conveying Posts and Messengers
Source: TTT
Esther 8:10, 14
Mordecai wrote in the name of King Xerxes and sealed it with the royal signet ring. He sent the documents by mounted couriers riding on swift horses bred from the royal mares. / The couriers rode out in haste on their royal horses, pressed on by the command of the king. And the edict was also issued in the citadel of Susa.