-Malik Shah I not being assassinated in 1092. His survival could have at least delayed the succession war that divided the Seljuk Empire and gave some wiggle room to the first crusader states.
Crossposting my earlier answer.
Divisions among Seljuk were less the entiere result of Malik Shah's death than a feature of Seljuk politics : Malik's sons and grandsons were
de facto independent governors of their respective provinces already before his death. And of course, the whole political situation which looked like a mixmash of a wasps' nest and a game of Clue (the caliph, with the poison, under the tent) : it already took his father and his vizeer, and if it failed you can bet his life it would be attempted again.
That being said, if Malik survived this assassination attempt long enough and, in the same time, prevented his familial puzzle of an empire to split thanks to his sheer political and military skills (the Seljuk ensemble wasn't doomed to split and fall as soon as Malik's corpse would be cold)
Well, you could arguably see a different Crusade, altough maybe not for what might be considered as obvious reasons : with a stronger and more threatening Seljuk presence in Anatolia, Byzantines could be strong-armed giving a deeper and more stable support to Crusaders even when it would become an annoyance as they were politically and militarily IOTL.
In the same time, the strength of a roughly unified Seljuk Empire might mud the Crusade into Anatolia and maybe Little Armenia, without real way for Crusader to go beyond the region : at this point, you could even have Fatimids lending an hand.
I agree, of course, that it makes a Crusader advance, let alone conquest, of Syria unlikely in the immediate aftermath : but the Seljuk Empire is structurally going down at this point, and that Arabo-Islamic princes wouldn't really correctly asset the nature of Crusade as they didn't IOTL. So, while Crusades would likely end up stopped before they could enter Syria, having Crusader forming some peripherical states to Byzantium (inside or outside its borders) may be doable, as well a renewal of advance in Syria with time : how long would it last and how successfully, tough...
-Nur-Ad-Din not dying in 1174. Had he lived, he could have enlarged the Zengid state to the borders of, roughly, the OTL ayyubids. How he would deal with the crusader states is still a bit fuzzy to me, so i welcome opinions.
Saladin more or less inherited, as you said, Nuradin's polities, but as well abitions, policies and tactics, at his benefit. I'm not sure we would see a major difference there for what matter Crusader States (altough, for Arabo-Islamic policies...)
-The byzantines winning the Battle of Myriokephalon and crushing the Sultanate of Rum. This could butterfly away the Fourth Crusade's diversion to Constantinople, and provide the byzantines with a better continental road to help the crusader states.
At this point, Crusader favoured the maritime way : it was quicker and less logistically problematic.
Not to say it wouldn't change anything, far from it.
In the short term, it wouldn't have immediate consequences (as the historical defeat didn't), but eventually it would make the later byzantine expeditions that took place historically being less about stabilizing the situation, and more ambitious on taking back coastal and central Anatolian, with a greater pressure on Turks that I would see not conquered, but submitted. As for Latin Syria, at this point, Turks represented no strategical concern, at the contrary of the Syro-Egyptian build up.
Consequences would be more visible, eventually, on imperial succession.
Manuel was one of the few Byzantine Emperors Latins held in reverence and put in a almost general good light by Latin chroniclers, as he managed to fight back Latin's ambitions while winning a good part of Latin elite by adopting, or at least trying to, several of their customs and institutional features when he dealt with them, seeing (as few emperors did)both the threat of Latins AND their potential as auxiliaries as well, and eventually living up to part of his expectations not only within the Empire, but in Oultremer and southern Italy.
Now, the working relationship with various Latin entities prooved shaly : the deep disunity and fierce independent culture of Latin nobles prevented a real overlordship to blossom, with big cultural and political gaps (the expeditions in Egypt, with the conflicting byzantine and yerosolemite interests, are a good exemple), but it was still a working relationship.
If we have a smoother succession, with Manuel policies apparently working out, allowing whoever inherits the purple to follow a similar policy towards Latins (open, but firm) especially with a prestige due to Myriokephalon's consequences, I think you might avoid some of the cultural and political backleash that followed the
Slaughter of Latins.
While Angeloi pointed at Latins as scapegoats for more or less everything (alamanikoi taxes are a good exemple of the pointing-and-disnouncing) did a great job increasing the tensions there, when Kommenoi and especially Manuel would have turned that into a more bilateral policy, nott adverse to Latins.
You might end up with at least a more or less benevolent neutrality acknowledging Constantinople's power (without that enforcing its overlordship). You won't get rid of raising tensions, especially when it come to Italian influence, but you could get away with a lot of most bloody and conflicting issues for a short while).
Baldwin IV of Jerusalem not having leprosy. For one with a crippling illness, he did quite a lot, but his accomplishments were undone because he could not produce an heir.
I think Baudouin IV's reputation to be overrated as well.
Less because of his skills, that still were relatively average (altough it had a good political intuition), than because his leprosy provoked some real unstability due to his inability to fulfill his military role (which was really stressed on in yerosolemite kingship).
Now, in a TL where he doesn't contract leprosy, it's certain that in spite of not-that-hyped skills, it would end up in a better situation.
Crossposting (again, sorry) from another thread.
Ayyubid takeover of Egypt and Syria is a given ITTL. Meaning the whole set of military pressure, harassment and threat of reconquest is still there, and it's not something easy to deal with. While during Amaury's reign, Latins could count on the important rivality between whoever controlled Egypt and whoever controlled Syria, this strategy is moot then.
We could argue that Amaury would live longer than IOTL, due to the absence of stress knowing his successor contracted leprosy (an illness that, for what matter medieval public opinion could be compared to the perception of AIDS in the 80's), possibly allowing a smoother succession.
I do think, tough, that Amaury's expedition in Egypt isn't really going to work out better than a glorified raid, probably significantly less so than the expedition of 1167-1168 before the clear hostility of the population, the Ayyubid control (altough Saladin doesn't have control of Northern principalties) and general weariness of Latin resources (the Armenian expedition wasn't exactly stellar).
The lack of more or less constant intrigues around Baudouin, due to his sterelity and his incompetency (in the medical sense) is certainly going to embetter the political situation of the kingom, making it more unified. It's a relative observation, tough : the Yerosolemite Kingdom was concieved as an idealized feudal entity, with a top-down/down-top vassalic relationship, meaning that the great feudataires had a large independence from the crown, and even vavassors (vassals of vassals) could intervene in the High Court (which shared much of the rulership with the king who, at times, was stuck with a more or less purely redistributive, military and of course vassalic role).
The interesting part there is which alliances Baudouin and which matrimonial unions he would eventually favour as, as it was said, it would be of great importance to gain military support.
An alliance with Montferrat still seems likely, due to their ties with Capetians and Honestaufen, with a union with one of the three daughters of Guilhèm V, instead of a marriage with the IOTL Guilhèm Lungaspada. One could argue, tough, that this union would be particularily anambitious.
If not Montferrat, then maybe Bourgogne with an union with Mahaut daughter of Eudes. The point is that it would search support among French and Imperial nobility.
Saladin is still going to have the upper hand on the conflict with Latin States by sheer ammount of ressources, political strength and skills. Maybe ITTL, tough, a safe and sound king that can assume the military function of his charge, and with a significantly (if not wholly, as pointed above) realm might simply do better, and avoid giving Saladin too much opportunities, while the kingdom in deep crisis up to a *Third Crusade IMO.
But with a significantly better hold for Poulains and Crusaders (in the same time, it's not that hard to think of a better hold than IOTL Third Crusade situation), it just might turns out better. Possible no civil war, more unified Poulains and more territory are good assests : we might even see a recapture of Jerusalem ITTL.
-Boniface of Montferrat being elected as Latin Emperor rather than Baldwin I. I hear Boniface was quite competent, so maybe he could have prevented the early disasters against the Bulgarians and provided the Latin Empire with a stabler base.
That wouldn't happen : Boniface de Monferret was one one hand, suspected being byzantophile by other crusaders, due to his familial and clientele relations with the imperial family, and on the other hand suffered from being an imperial vassal, while French crusaders (forming the main part of the expeditions) really frowned upon the idea of being under a possible imperial suzerainty trough Boniface's own situation.
I agree that a continued political friendship between "Byzantium" and the Crusaders could benefit both parties, and possibly ensure a longer survival of the Frankish states in the east. TBH, I got the TL out of the premise that only fundamental changes in the course and aftermath of the First Crusade could have preserved the Jerusalemite kingdom. I don't know if even a more successful 2nd Crusade (with the capture of Damascus) would help so much if the Zengids remained at large and succeeded in conquering Egypt.
