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.
KJV
And he wrote in the king Ahasuerus’ name, and sealed [it] with the king’s ring, and sent letters by posts on horseback, [and] riders on mules, camels, [and] young dromedaries:
ASV
And he wrote in the name of king Ahasuerus, and sealed it with the king’s ring, and sent letters by post on horseback, riding on swift steeds that were used in the king’s service, bred of the stud: