The following excerpt is quoted from Tarikh al-Tabari (Eng. Translation v.33 pp. 5-7). It describes the armed uprising of sayyidina Muhammad b. al-Qasim, a direct descendant of Prophet (Sallallahu alaihi wasallam) through the line of Imam Zain-ul-Abidin (he was Imam Zain-ul-Abidin’s great-grandson). This uprising took place at Taloqan (modern-day Afghanistan) in the Takhar province, including in the surrounding mountains:
In the year 219 H (834 CE):
Among the events taking place during this year was the rebellion, at al-Talaqan in Khurasan, of Muhammad b. al-Qasim b. ‘Umar b. ‘Ali b. al-Husayn b. ‘Ali b. Abi Talib, summoning people to the cause of “the well-pleasing one from the family of Muhammad” (al-rida min al Muhammad). A considerable number of people there rallied to his side, and military encounters took place in the vicinity of al-Talaqan and the mountains there between him and Abdullah b. Tahir’s commanders. In the end he and his followers were defeated, and he fled, seeking a certain distrinct of Khurasan whose people had been in correspondence with him. He reached Nasa, where the father of one of his followers lived, and this follower of his at that point went along in order to greet his [the follower’s] father. When he met his father, the latter asked him the news, so the man told his father about what had happened to them and how they were making for so-and-so district. The man’s father thereupon went to the governor of Nasa and told him about Muhammad b. al-Qasim’s plans. It has been mentioned that the governor gave the father 10,000 dirhams for information that would lead him to Muhammad b. al-Qasim. The father accordingly gave him information about Muhammad b. al-Qasim’s whereabouts.
So the governor went along to Muhammad b. al-Qasim, arrested him, placed him in firm custody, and dispatched him to Abdallah b. Tahir. The latter sent him to al-Mu’tasim; he was brought to him on Monday, the fourteenth of Rabi’ II (April 28, 834) and was then imprisoned, so it has been mentioned, at Samarra in the house of Masrur al-Khadim al-Kabir in a narrow cell some three by two cubits only. He remained there for three days and was then transferred to a more commodious place than the previous cell, food was given to him regularly, and a group of persons was appointed and charged with the task of guarding him. When it was the night of ‘Id al-Fitr (the thirtieth of Ramadan 219, the night of October 8 – 9, 834 and everybody was distracted by the festival and the rejoicings, he devised a stratagem for escaping.
It has been mentioned that he fled from jail by night and that a rope was let down for him from an aperture in the wall of the upper part of the house, through which light penetrated to him. When his jailers came next morning with food of his breakfast, he was missing. It has been mentioned that a reward of 100,000 dirhams was offered for whoever might give information that would lead to Muhammad b. al-Qasim; the public herald proclaimed this, but no further news was heard of him. (Uncertainty about Muhammad b. al-Qasim’s fate is reflected in stories given by Ma’sudi, including the one that he returned to al-Talaqan and was expected by the Zaydis to return as a Mahdi after his death; Isfahani regards it as most probable that he escaped to Wasit.)