Sahl (?) in the battle of two brothers
Towards the end of the 1st decade of 9th century CE
Image credit: www.peoplepill.com
Caliph Harun al-Rashid named Al-Amin as his successor and Al-Ma’mun as the second. Al-Ma'mun was offered the governor position in Khurasan and al-Rashid’s another son, al-Qasim was declared as the third successor after Al-Amin and Al-Ma’mun. Calpih Harun al-Rashid died in the year 809 and Al-Amin as per his father’s instructions. However, things turned sour for the reasons we might need to digress to much into the historical background which we won’t do here.
Al-Amin broke his father’s words and announced his son Musa as his successor. This is against his father’s words as al-Rashid wished for his 2nd son, Al-Ma’mun to be the successor of Al-Amin. This created an irreparable rift between the two brothers.
Muhammad (Al-Amin) sent 'Ismah b. Hammad b. Salim to Hamadhan with a thousand men and put him in charge of military affairs of the districts (kuwar) of alJibal. He commanded him to stay at Hamadhan and to send his vanguard to Sawah. ('Ismah) appointed his brother 'Abd alRahman b. Hammad to be his deputy over the guard (tiaras). AlFadl b.al-Rabi' and `Ali b. Isa began inflaming Muhammad and urging him to depose al-Ma'mun and have allegiance sworn to his own son Musa. 
It looks like al-Fadl b.al-Rabi (vizier/astrologer of Al-Amin) had a lot of influence and he took a lot actions within his power to take Al-Ma’mun out of the equation. If we read the history, it also appears as it he was a bit too hasty to be a decision maker.
In this year, in the month of Rabi` 1, Muhammad b. Harun confirmed his son Musa over everything for which he had made him his deputy and made `Ali b. Isa b. Mahan master of all his affairs. 
The year is 810-811 CE (Islamic year 195). Rabi’ 1 month is the December of 810. There are two Rabi’ months, Rabi al-awwal and Rabi al-thani. Rabi’ 1 month is Rabi al-awwal which is from 2 December 810 to 31 December 810. So, it was during the December of the year 810, all the affairs were associated with Musa (son of Al-Amin) and Al-Ma’mun, the actual successor was side-lined. All this was known to Al-Ma’mun and his people. Due to this, the rift became more stronger and the gap widened between the two brothers.
Before all this in Safar (November 810), Al-Amin stopped prayers for Al-Ma’mun and al-Qasim. He demanded that prayers should be for only him and after him not anyone else. Michael Fishbein had written that Musa was only a child at that time.
He acted in the matter on the advice of al-Fadl b. al-Rabi. Concerning this, a poet said:
The caliphate has been brought to ruin by the vizier's malice, the commander's (amir) dissoluteness, and the counselor's ignorance.
Fadl is a vizier and Bakr a counselor who(se) desire what will bring about the commander's death. 
First step - The Battle of Rayy
Clearly, Al-Amin was not acting out of his right mind and his thoughts and vision were overshadowed at the whim of his vizier. During this time, Al-Ma’mun was lying low and did not retaliate much except for he was only ready for whatever was about to come. It is obvious that Al-Amin would one day march with his armies to Khurasan. The troops left to al-Rayy (modern day Shehr e-Rey, Iran) in order to fight the forces of Al-Ma’mun.
They left the evening of Friday, the 15th of Jumada II of the year 195 (March 14, 811). He left in the late afternoon of that day, between the Jum'ah prayer and the afternoon (asr) prayer, for his camp on the Bin Canal. 
15th of Jumada II of 195 is the 14th of March 811. There are two Jumada months, Jummada al- awwal and Jumada al-thani. 2nd Jumada month of Jumada al-thani ranges from 28 February 811 to 30 March 811. In the evening of Friday needs better understanding for us to construct a chart as we don’t have an exact time. Jum’ah prayer is the one during the noon after the passes the highest (Midheaven) and the next prayer is Salat al-‘asr which is during the late part of the afternoon. It is mentioned that the troops left between the noon prayer and the afternoon prayer. Asr usually seems to be fall between 16:30 to 17:00 hours. Since we have the information that they left in the middle of the two prayers, I narrowed down the time to around 15:30 to 16:30 hours. I am sticking to 14:50 hours, when Leo was rising.
Ruler of the Ascendant, the Sun is placed in the 8th house in the bounds of Mars which is a very troublesome position. Symbolically, due to Leo rising, we know that the troops of Al-Amin should have stayed where they were instead of deciding to march forward. On the other hand, Al-Ma’mun and his men decided to stay back, and they believed that they can outlast the enemy by being at their own backyard.
He (al-Mamnun) wrote to Tahir b. al-Husayn, al-Rayy. He commanded him to secure his area, gather his outlying districts to himself, and be in a state of alert and (in) preparation for an army if it invaded him, or a foe if it attacked him. So the latter readied himself for war and prepared to repel Muhammad from the province of Khurasan.
Abdallah (al-Ma'mun) sent to al-Facil b. Sahl and asked his advice in the matter of Muhammad. "Commander," he replied, "give me a respite today, and I will bring you an opinion tomorrow." He (Sahl) spent that night considering what was best to do. In the morning, he came to (Al-Ma’mun) and told him that he had considered the stars and had seen that he would win and that the result would be in his favor. So 'Abdallah (al-Ma'mun) remained in his place and made up his mind to fight and contend with Muhammad. 
Al-Ma’mun had a vizier named al.Fadl b.Sahl who I am not sure if this is the astrologer Sahl ibn Bishr, but it looks like he is the one. Based upon the advice of Sahl, Al-Ma’mun chose fight back from Khurasan and wrote a letter to his commander t al-Rayy (Rayy) to be ready in case of any attacks from Al-Amin.
2nd and 11th ruler debilitated in Pisces, victory (11th ruler) seem largely at stake. Moreover, Jupiter is debilitated in the 6th house which can signify that there is no putting up a fight against the enemy at all. Mars is placed in the 8th house of Pisces. Pisces is not a good sign for Mars to be in especially for the matters concerning war. The Sun is in the 8th house of aversion which indicates that the king is out of equation (Al-Amin) and there is nothing much that is going to happen which will benefit him. The Lot of Fortune in the 7th house seems to be indicating that the opposite side has more fortune.
Since there is no correct time, I decided not to write about the finer details of the chart. But it fascinating as to how things happened during that point in time.
No one would have really elected time to send their troops to al-Rayy but may be it would have been significant for the Al-Amin camp to take note of what the stars (astrology) had to say which is exactly the way Al-Ma’mun did before deciding to stay back without moving from their place and just placing an army of a commander at al-Rayy to have better control over things.
Later, the Battle of al-Rayy (modern day Shehr-er-rey, Iran) began on 1 May 811 CE for which we don’t have the time when the war began. I will sign off by leaving you to decide upon the below chart which was cast at 06:00 hours in the morning which is usually, close to the sunrise time.
 Page# 44, The History of al-Tabari – Volume 31, The War between Brothers, translated by Michael Fishbein, University of California, Los Angeles, State University of New York Press.
 Page# 44/45, The History of al-Tabari – Volume 31, The War between Brothers, translated by Michael Fishbein, University of California, Los Angeles, State University of New York Press.
 Page# 47, The History of al-Tabari – Volume 31, The War between Brothers, translated by Michael Fishbein, University of California, Los Angeles, State University of New York Press.
 Page# 50/51, The History of al-Tabari – Volume 31, The War between Brothers, translated by Michael Fishbein, University of California, Los Angeles, State University of New York Press.
 Page# 73, The History of al-Tabari – Volume 31, The War between Brothers, translated by Michael Fishbein, University of California, Los Angeles, State University of New York Press.
© Aswin Subramanyan 2020
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