I know that the first Crusade was the bloodiest but were the Crusaders really worse than the Caliphates?
I read that in the Kingdom of Jerusalem both Muslims and Jews had their own courts as well as the Latin court and an Arab Christian called Saad was made Martial of Jerusalem.
Ibn Jubayr seems to have been shocked that Muslims were not obligated to follow Shariah law in the Kingdom of Jerusalem.
Could it be the Crusaders after the 1st Crusade were actually more moderate or secular than the Muslim dynasties they were fighting?
What about the alleged civilian massacres - can some one enlighten me on that?
Were taxes on Muslims worse during the Crusaders?
Ibn Jubayr states:
This is one of the misfortunes afflicting the Muslims. The Muslim community bewails the injustice of the landlord of its own faith, and applauds the conduct of its opponent and enemy, the Frankish landlord, and is accustomed to justice from him.
Which seems like a veiled attempt at saying Muslims under the Franks preferred Frankish law.
There's a big difference between the Crusades, and the Crusader states. Some people were the same, others were different. Certainly the crusaders were awful: they massacred Jerusalem and killed many peasants on their way. They broke their oaths to return the land they'd captured to the Emperor (which was a big deal at the time). The fourth crusade never got to the Middle East: instead, they sacked Constantinople and broke up Greece into their own territories. Byzantium later re-emerged, but never regained its power, allowing the Turks to overrun Greece and the Balkans and even threaten Vienna.
The Crusader states, on the other hand, were multi-cultural trading powers, with Latins on the top. They were heavily involved with the Italian trading city-states, such as Genoa and Venice, as they were the gateway to the Middle Eastern trade. They didn't forcibly convert Muslims, but I don't know if they charged them higher tax.
Most of what I know I got from my old friend Stephen Donnachie's PhD paper "Reconstruction and Rebirth: the Latin Kingdom of Jerusalem 1187-1233", but I don't remember all the details exactly (hopefully someone else can provide more detail).
About misconceptions about the Crusaders, I'd say there are two important things to remember. First, they were not really pro-Christian, they were pro-Latin Catholic (of course, they considered themselves pro-Christian because they considered only Latin Catholics were proper Christians). They were bad allies at best with the Orthodox (and ended up wrecking the Orthodox Church's power in the 4th Crusade), and treated local Christians barely better than Muslims (it's honestly possible they didn't know that many of the locals were Christians, initially). Secondly, they initially knew virtually nothing about Muslim theology or local geo-politics. They didn't seem to be aware that the Seljuk Turks didn't control Jerusalem, for example, or that the Fatimids and Seljuks followed different branches of Islam. And then there's the song of Roland, in which Muslims worship 3 gods: Mohammed, Termagent, and Apollo. Saying this, the Crusader States seem to have developed a much better understanding of Islam and the local politics, at times allying with local Muslim rulers against others.
I'm supposed to be marking student essays at the moment so I'm going to have to be brief, but if you have more questions I can try and answer them later. I also can't comment on courts at all really.
It has already been mentioned that we have to draw a distinction between Crusades and the Crusader States. After the end of the First Crusade the Latin Crusaders who chose to resettle in the Holy Land had to quickly adapt to life in a new land with a very new political climate. While not universal, they tended towards behaving more moderately in their relationships with Muslims and native Christians than their European counterparts. There are exceptions where individuals who were resident in Syria for a long time were still pretty barbaric (Reynald of Chatillon being a notorious example) but this wasn't really the norm. I've encountered the idea that life for a Muslim under a Latin Syrian lord could be better than a similar life under a Muslim lord would be. This has primarily been attributed to the idea that the Latin rulers were very much in the minority and were constantly worried about insurrection from the native populace, and so couldn't really afford to be as oppressive as they might like. Muslim rulers had no similar problems with their population, since they largely followed the same religion as the people they ruled (this is a bit of an oversimplification, there are cases such as Saladin's rule in Egypt where a Sunni ruler had to oversee a primarily Shia populace).
One thing that must be born in mind in particular with this subject is how different the standards of the Middle Ages were to those we have now. Many actions we see as horrifying and barbaric were, if not entirely the norm, not unusual for the Middle Ages. For example, the massacre of the populace of Jerusalem at the end of the First Crusade was pretty horrible, but it is by no means the only city to be completely massacred as a result of medieval warfare. Many of the atrocities we see in the Crusades were actually pretty common to medieval warfare and weren't all that surprising to Muslim onlookers at the time. What often complicates this debate is the legacy of Saladin, who was a remarkably merciful and reasonable general, and he is often compared to the more 'bloodthirsty' Richard I. However, Saladin was a real outlier and if you compare the Crusaders to the Mamluke generals like Baybars and his descendants you see pretty much the same 'atrocities' committed by both sides.
I'm not trying to excuse the Crusaders actions here, or to damn the Muslim rulers either, instead this was pretty much the norm for medieval warfare during this period. Medieval war was horrible and the line between non-combatant and legitimate target was often not clearly defined. An opposing lord supplied his armies on the backs of his peasants, so attacking his peasants could be seen as a legitimate method of undermining his ability to wage effective war against you.
For Crusades history in general I really like the work of Thomas Asbridge, but Jonathan Riley-Smith is also worth a read if you want something a bit shorter.
For Muslim perspectives Amin Maalouf's Crusades Through Arab Eyes isn't an academic work but it's easy to find a copy of and very approachable. For something more academic you might want to check out Carole Hillenbrand's Crusades: Islamic Perspectives or Francesco Gabrieli's Arab Historians of the Crusades
Maurice Keen's Medieval Warfare has a good essay on the concept of noncombatants in medieval Europe and how it changed over the course of the Middle Ages.