Ṭáhir b. 'Abdu`lláh, who was in control of Khurásán, was unable to govern his province with firmness; and at this time a man called “the Veiled Sayyid” (Sayyid-i-Burqa'í) revolted at Baṣra and Wáṣiṭ in Sawád. This man is better known as “the Leader of the Ethiopians” (Ṣáḥibu`z-Zanj), and 'Alí, in some of his apocalyptic writings (<Arabic>), gave tidings of his appearance, saying:
<Arabic>
Now it was at this juncture, while the Caliph and Ṭáhir b. 'Abdu`lláh were occupied with these matters, that Ya'qúb b. Layth, a brave and ambitious man, revolted and became powerful. For many troubles distracted Khurásán, where rebels and robbers arose on every side, but Ya'qúb b. Layth aṣ-Ṣaffár (“the Copper-smith”) was the most cunning and powerful of all. Originally of lowly origin and humble circumstances, he gathered a band of followers round him, and, owing to the weakness of the government, succeeded at last in dispossessing the governor of Sístán appointed by Ṭáhir b. 'Abdu`lláh. He was then proclaimed king, marched on Khurásán, and seized the territories of Muḥammad b. 'Abdu`lláh [b.] Ṭáhir, so that at length the Caliph thought it best to make over Khurásán to his control. Having taken Níshápúr he came to Dihistán, and sent secretly to <Arabic>, promising him Gurgán and Astarábád if he would abandon Sayyid Ḥasan and help him. So on the 1st of the month of Urdí-bihisht, A. H. 260 (Oct.—Nov., A. D. 874), they came together to Sárí and fought with Ḥasan 'Aqíqí, who fled to ´Amul without halting, pursued by Yá'qúb b. Layth with lanterns and torches. The Sayyid Ḥasan came from ´Amul to Rúyán, while his followers abandoned him on all sides. Ya'qúb b. Layth proceeded to Kalár, and Ḥasan retreated to Shírú. Ja'qúb sent a message to the people of Shírú promising not to enter their territories if they would hand the Sayyid over to him, but they refused, incited thereunto by Kawkabán, one of the chief men of the place, and Ya'qúb (f. 116b) was forced to retire. His baggage was cut off and plundered by the Daylamites, and he went to Kajú, and, by torture and threats, extorted from the people of Rúyán two years’ taxes, so that they were left without food or clothes. He then made. Layth b. Fana governor of Rúyán, Pádhúsbán governor of Ṭabaristán, and Qásim b. Muslim al-Khurásání, one of his own men, governor of Jálús, while he retired to ´Amul. Immediately the people of Jálús attacked their new governor, burned his palace, and slew all his men. News of this was brought to Ya'qúb, who returned, cut down the trees and burned the houses, and then marched on to Kandasán by way of Kalár, and thence to Rúyán. But all his camels were destroyed by the fly, rain and thunderstorms came on, and he entrenched himself in ´Amul. No sooner had he arrived there than he heard that Ḥasan b. Zayd was coming, whereupon he emerged to the coast, and Ḥasan fled to Kúhpáya. Ya'qúb then marched to Kurd-ábád by way of Nátil, exacted two years’ taxes from the people of the plain, and thence returned to ´Amul and Sárí. He continued altogether four months in Ṭabaristán, and then retired from Sárí by way of Qúmish to the neighbourhood of Ray, and wrote to his deputy in Sístán to release the 'Alawís whom he had taken prisoner and give them money to go to their own country. One of then was Sayyid Ḥasan b. Zayd’s brother, Abú 'Abdi`lláh Muḥammad b. Zayd.
As soon as Ya'qúb-i-Layth had quitted Ṭabaristán, Ḥasan b. Zayd came to Sárí with an army of Daylamites, and the people again gathered round him. He advanced without halting to Gurgán, when he was met by the news that his brother, mentioned above, had been released by Ya'qúb, and was approaching. He went out to meet him with his whole army, and in Ṣafar, A. H. 263 (= November, A.D. 876) they met, and halted for the remainder of that month and the whole of Rabi' I at Gurgán, after which he returned to Ṭabaristán to see his mother. A predatory band of several thousand Turks, blood-thirsty infidels, had entered Dihistán (f. 117a) and were preparing to attack Ṭabaristán. Ḥasan b. Zayd was then at Gurgán. He placed Muḥammad b. Aḥmad Khurásání in command of the vanguard, consisting of 2000 Daylamites, and himself took command of the centre. They met the infidels at Shúra in Dihistán, and completely routed them. Muḥammad b. Tamím, known as Mardán-kulah was killed; and Ḥasan b. Zayd fought with great bravery, and pursued the fugitives till they were all killed or dispersed. His courage on that day marked an epoch.