Muḥammad b. Zayd, with the title ad-Dá'í al-Kabír (“the Great Missionary”) received the oath of allegiance from the people of Ṭabaristán. He was at the time of his brother’s death in Gurgán, and his son-in-law, Sayyid Abu`l-Ḥusayn, seized the money which was in the treasury and expended it in inducing the people to swear allegiance to himself, which most of the Daylamite chiefs did. He was also joined by the Ispahbad Rustam the son of Qárin and Pádhúsbán.

When Muḥammad b. Zayd heard the news of his brother’s death, he advanced on ´Amul with hís army, many of whom had been secretly won over to the interest of Sayyid Abu`l-Ḥusayn, who tried to persuade some of them, such as Laythám the son of Wardán, and Abú Manṣúr Mahdí b. Mukhayyas, to slay Muḥammad b. Zayd at Ribáṭ-i-Hafṣ. They refused to kill him, having eaten his bread and salt, but deserted him, and turned back to Gurgán. He too turned back thither, but the inhabitants refused to admit him, and he therefore took up his quarters in the village of Zawín. Abu`l-Ḥusayn sent money and robes of honour for the people of the city, and bade them let Muḥammad b. Zayd remain where he was; and he dared not put his head outside Zawín until Ráfi' b. Harthama returned defeated from Khurásán, and sent for Mahdí b. Mukhayyas, who was his servant, to come and meet him. Mahdí paid no heed to this message, whereupon Ráfi', divining Muḥammad b. Zayd’s condition, sent (f. 119b) trusty men to him, brought him to his quarters and fought and defeated Mahdí b. Mukhayyas, who fled to Khurásán. Laythám-i-Daylam went to Abu`l-Ḥusayn, and 'Alí b. Surkháb was taken prisoner by Mahdí, but fled from him on the day of his defeat. Ráfi' handed over Gurgán to Muḥammad b. Zayd and returned to Khurásán. One day Abu`l-Ḥusayn began to oppress his followers in order to enrich himself, and these consequently wrote in secret to Muḥammad b. Zayd invoking his assistance. He, having collected an army, arrived at Sárí on Wednesday, the first of Jumádá I, A. H. 271 (= October 25, A. D. 884), and Abu`l-Ḥusayn, who was there, fled from him to ´Amul, whence he started at night to join Laythám and Nu'mán at Jálús and go to Daylam. On the Sunday Muḥammad b. Zayd reached ´Amul, whence on the Tuesday he moved on to the village of Banafsh, whence he proceeded by night to Jálús, and there seized Abu`l-Ḥusayn, with Laythám and the other Daylamites who were with him, with much spoil. That night he went on to Khwájak, and reached ´Amul, where, on Friday, the 6^th of Jumáda I, he was crowned king. Abu`l-Ḥusayn, whose power had endured ten months, was cast into bonds, and pardon was proclaimed to his agents and officers, who there­upon submitted, and were made to render account of the moneys they had collected for their master. He also brought in Abu`l-Ḥusayn’s sister, who was the widow of his late brother Ḥasan b. Zayd, and took from her all her jewels and gold ornaments, after which he released Abu`l-Ḥusayn, bidding all those from whom he had exacted money recover it from him. Thereupon the jurisconsults of ´Amul bore wit­ness against him of exactions amounting to a million dir­hams, upon which he was again cast into bondage, and sent with Laythám-i-Daylam to Sárí, after which no one ever saw them again, and it was said that they were killed on the road thither.

So soon as Muḥammad b. Zayd was thus established as ruler of Ṭabaristán, he set out for the highlands against the Ispahbad Rustam the son of (f. 120a) Qárin, drove him out of the kingdom, and sent him to 'Amr b. Layth the Ṣaffárí, who interceded for him; and pardon was granted to him on condition that he should swear henceforth to maintain no army, and to send all that he had to Muḥammad b. Zayd, and to pay all the tax and tribute which he had with­held. And Muḥammad b. Zayd established his capital at Gurgán where many retainers gathered round him, although he was unable to give him pay.