Then came the year 176 AH.

In that year Yaḥyā ibn ʿAbd Allāh ibn al-Ḥasan ibn al-Ḥasan ibn ʿAlī ibn Abī Ṭālib emerged in the region of Daylam. A vast multitude rallied to him, his strength grew formidable, and people flocked to him from every district and province. The news alarmed Hārūn al-Rashīd, so he dispatched al-Faḍl ibn Yaḥyā ibn Khālid al-Barmakī at the head of fifty thousand troops and appointed him over the mountain districts, Rayy, Jurjān, Ṭabaristān, Qūmis, and other territories. Al-Faḍl set out in magnificent state, while letters from al-Rashīd, together with robes of honor, gifts, and benefactions, reached him at every stage of the journey.

Al-Rashīd also wrote to the ruler of Daylam, promising him one million dirhams if he would help bring Yaḥyā out to them. At the same time al-Faḍl corresponded with Yaḥyā, assuring, enticing, and encouraging him, pledging that, should he come, al-Faḍl would obtain pardon for him from the caliph. Yaḥyā refused to leave, however, until al-Rashīd himself sent a writ of safe-conduct in his own hand. Al-Faḍl informed the caliph, who was delighted and viewed the matter most favorably. Al-Rashīd thereupon wrote the guarantee with his own hand, had the judges, jurists, and the elders of Banū Hāshim—including ʿAbd al-Ṣamad ibn ʿAlī—bear witness to it, and dispatched the document along with very many gifts and presents. When all this reached al-Faḍl, he forwarded it exactly as it was to Yaḥyā ibn ʿAbd Allāh.

Al-Faḍl then escorted him and entered Baghdad in his company. Al-Rashīd went out to meet Yaḥyā, honored him, showered him with gifts, and the Banū Barmak rendered him extraordinary service—so much so that Yaḥyā ibn Khālid used to say, “I served him personally and with my sons.” Through this deed al-Faḍl’s standing with al-Rashīd soared, for he had effected a reconciliation between the ʿAbbāsids and the Fāṭimids. Concerning this, Marwān ibn Abī Ḥafṣa ibn Yaḥyā composed verses in his praise:

You triumphed—may a Barmakid hand never wither—
By which you sewed up the rent that split Hāshim;
When those who would mend it despaired of its closure,
They withdrew, declaring, “It will never be whole.”
Your two hands have now won a stratagem of glory
Whose memory endures through the pilgrimage seasons;
And the lot of kingship keeps falling to your share
Whenever the competitors’ lots are drawn. (1)

They relate, however, that al-Rashīd later turned against Yaḥyā ibn ʿAbd Allāh ibn al-Ḥasan and altered his attitude toward him—some say he imprisoned him—then summoned him while groups of Hāshimites were present. The caliph produced the pledge of safety he had sent and asked Muḥammad ibn al-Ḥasan, “Is this guarantee valid?”

He replied, “Yes,” whereupon al-Rashīd became angry with him. Abū al-Bakhtarī said, “This guarantee is worthless; pass whatever judgment you wish concerning him,” and he tore the document apart and spat on it.

Al-Rashīd then turned to Yaḥyā ibn ʿAbd Allāh and said, “Hey, hey!” smiling the smile of an angry man, and added, “People allege that we tried to poison you.”

Yaḥyā answered, “Commander of the Faithful, we share bonds of kinship and right. Why do you torment and imprison me?” Al-Rashīd was moved to pity, but Bakkār ibn