Something I have been seeing more and more over the last few years is just how significant the Saturn/Mars conjunctions are in the greater scheme of national events. It is a subject that several of the Persian authors spent time documenting in their own national forums. The correlation of events like riots and rebellions and overthrowing of law and order and removal of caliphs etc. to the Saturn/Mars conjunctions in Cancer is documented especially in Abu Ma’shār.
“Related to the superior planet furthest from the world of generation and corruption, i.e. to Saturn, is the indication for matters of Beginnings like religions, dynasties, and whatever lasts for a long time, since it is like the beginning for the other celestial bodies in terms of height… Related to the third of these planets in order, i.e. to Mars, is the indication for wars, strife, and the like, being as it were, the decline to the final ends of things, because the ends of things indicate destruction of their orderly arrangements after their perfection, and corruption of their regularity.” 
“ We say that the most distinct of the indications occurring as a result of the influence of the conjunction of Saturn and Mars is in the sign of Cancer, since this sign is the detriment of Saturn and the dejection of Mars, and since the indication of this sign with Jupiter is for Iraq… Each sign has an indication for one of the regions, because sometimes a city is related to one of the signs and the predominant <planet> over it (the city) is not the lord of that sign. For example, the indication of Cancer with Jupiter is for Iraq because Jupiter is predominant over <the degrees of> the sign indicating Iraq, i.e. from its 19th to 26th degree. For the extent of these degrees of the sign of Cancer is the term of Jupiter, indicating Iraq… The presence of the malefics in it and their aspecting it from quartile or opposition indicate calamity, the change of rule, and bloodshed, if the triplicity to which the conjunctions shifts should necessitate that, especially when the two malefics are in conjunction without the aspect of the benefics.”.” 
Abu Ma’shār goes on to examine this conjunction (i.e. Mars & Saturn in Cancer) with regards to changes in the rule over the Islamic empire. While his examination focuses on the conjunction in Cancer it is not entirely clear why Cancer is associated so strongly with Islam. That answer I believe lies in the chart of the beginning of Islam which we find in Māshā´allāh.
“And Māshā’allāh said that when he looked in this image [at] the places of its planets, he found the strongest of them and the greatest of them in testimony, to be Saturn: because he was entering into the Ascendant, and he is the lord of its exaltation, and the Moon (the lord of the light of the night) is pushing her management to him from the tenth (by number) and the ninth (by division), the place of prophethood, and Jupiter is pushing his management to her. And he found Mars in Gemini (and it is the ninth by number), in the highest [part] of the belt, climbing to its highest point, receiving the management of the Sun, Venus, and Mercury (through his retrogradation)… Because the place of the Moon is in upper midheaven indicates that he will be secure from being killed and because Venus escaped combustion this indicates that he will meet hardships and go into hiding for a while; then he will establish connections and be strengthened, and become known, and the people of his doctrine will rule. Because the place of the moon is in upper midheaven and Mars is in the house of religion, these indicate that he will seek religion and its being established by struggle. And because of the connection of the moon with Venus the people of his doctrine will have the nature and manners of Venus …”
What makes Cancer so relevant to the rule and rulers in the Islamic empire was the fact that the sect light, the Moon, was in the midheaven of the chart and indicated “the people of his doctrine shall rule.” It is no wonder that the Mars/Saturn conjunction in Cancer was relevant for each real change in the dynasty within the Islamic empire! This is exactly what Abu Ma’shār was indicating when he talks about how the signs indicate empires or countries and cities; “…each sign has an indication for one of the regions…”
Read the entire article here.…
 Ibid Part I, Chapter 1:7 (p.7)
 Part II, Chapter 8:3 – The Book of Religions & Dynasties (On the Great Conjunctions) – by Abu Ma’shār, translated by Keiji Yamamoto and Charles Burnett from the Arabic original, Brill 2000.
 f230v & f231r (pp. 48-50) – The Astrological History of Māshā´allāh – translation and comments by E.S Kennedy & David Pingree – Harvard University Press 1971
 That is, he is retrograding into Libra.
 Mars is in the middle of Gemini, advancing towards the solstitial point at 0° Cancer, the most northern zodiacal point in declination.
 An interesting comment; It is clear under the reign of Islam that political correctness was the ‘de jour’ thing to do. It being Mars and knowing history at the time of Māshā´allāh, it would have been more precise to say “and it being established by war”! Of course the cancel culture thrives under totalitarian rule; but there the cancel would have included their head and not just their livelihood like it is today!
 And here is the origin of Venus indicating the people of Islam!