In 802 Nicephorus (Ni-ceph'-o-rus) usurped the throne of the Eastern Empire . He sent ambassadors with a letter to Harun to tell him that the tribute would no longer be paid. The letter contained these words:
"The weak and faint-hearted Irene submitted to pay you tribute. She ought to have made you pay tribute to her. Return to me all that she paid you; else the matter must be settled by the sword."
As soon as Harun had read these words the ambassadors threw a bundle of swords at his feet. The caliph smiled, and drawing his own sword, or cimeter (sim'-e-ter), he cut the Roman swords in two with one stroke without injuring the bald, or even turning the edge of his weapon.
Then he dictated a letter to Nicephorus, in which he said:
"Harun-al-Rashid, Commander of the Faithful to Nicephorus, the Roman dog: I have read thy letter. Thou shalt not hear, thou shalt SEE my reply."
Harun was as good as his word. He started that day with a large army to punish the emperor. As soon as he reached Roman territory he ravaged the country and took possession of everything valuable that he found. He laid siege to Heraclea (Her-a-cle'-a), a city on the shores of the Black Sea , and in a week forced it to surrender. Then he sacked the place.
Nicephorus was now forced to agree to pay the tribute. Scarcely, however, had the caliph reached his palace in Bagdad when the emperor again refused to pay.
Harun, consequently, advanced into the Roman province of Phrygia , in Asia Minor , with an army of 15, 000 men. Nicepherus marched against him with 125, 000 men. In the battle which followed the emperor was wounded, and 40, 000 of his men were killed.
After this defeat Nicephorus again promised payment of the tribute, but again failed to keep his promise.
Harun now vowed that he would kill the emperor if he should ever lay hands upon him. But as he was getting ready to march once more into the Roman provinces a revolt broke out in one of the cities of his own kingdom; and while on his way to suppress it the great caliph died of an illness which had long given him trouble.