It may also be said:
Second, there are numerous cloaks of initiation, the two best known being one traced to Umar and another traced to Alī. The cloak traced to Umar has two chains of transmission: one through Uways al-Qaranī and another through Abū Muslim al-Khawlānī. As for the cloak attributed to Alī, its chain runs through al-Hasan al-Basrī. Later authorities connect it through Ma'rūf al-Karkhī, for al-Junayd kept company with al-Sarī [al-Saqatī] (1), and al-Sarī undoubtedly kept company with Ma'rūf al-Karkhī.
The chain, however, breaks off at Ma'rūf. They sometimes claim that Ma'rūf kept company with Alī ibn Mūsā al-Ridā, but this is categorically false. It was not mentioned by those who compiled accounts of Ma'rūf using established, continuous chains of transmission, such as Abū Nu'aym and Abū al-Faraj ibn al-Jawzī in the book he wrote on the virtues of Ma'rūf. Ma'rūf lived in seclusion in al-Karkh, whereas al-Ma'mūn had appointed Alī ibn Mūsā as his heir apparent (2), to succeed him, and had made green dress his official emblem. He later reversed this and restored black as the emblem.
Ma'rūf was not among those who met (3) Alī ibn Mūsā. No reliable transmitter reported that he had met him or learned anything from him; indeed, it is not even known that he ever saw him. Nor was Ma'rūf his gatekeeper, nor did he embrace Islam at his hands. All of this is false.
Regarding the other chain, they claim that Ma'rūf kept company with Dāwūd al-Tā'ī. This claim is likewise baseless and is not mentioned in the well-known accounts of his life. The chain of the cloak also states that Dāwūd al-Tā'ī kept company with Habīb al-'Ajamī, but no factual basis for this has been established either.