To add on a bit what Nico already said, most Amarr players don't go as far as to say the Amarr faith is space Catholocism/Islam. While in old PF (might still be in PF) it boldly stated the roots of the Amarr religion stemmed from a branch of the Catholic church, that's not what it is anymore. Obviously over the many a years since the collapse of the Eve Gate, it evolved into something completely different, and you can't say it's anything mostly resembling to a specific RL religion anymore. I think that's what a lot of us Amarr/Khanid RPers see, and thus hesitant to call it space Catholocism/Islam.
However, using bits and pieces of RL religion/cultures as references to paint a better picture of the Amarr religion, that a lot of us do. I know a few of us say Persian/Arabic cultures, and I myself see things like some Egyptian, Roman, Hebrew and European Renaissance references in it.
One more thing, do be careful on what your character claims to be a holder of. I'm not saying this in reference to the Matari planets she claims to be a dutchess of at all. More in reference to any of the Khanid territory. As far as I know, I don't know anyone who claims to own the Palas system, so that should be okay. But I say this more so, just in case, be wary that changing what you say your character owns could potentially step on another player's RP, if said player already made a claim to such territory.
The Amarr religion stems per PF from the
Unified Catholic Church of Mankind. There has been much debate about what this church exactly is, but we can be quite sure that it's
not the Roman Catholic Church or any other church we know now.
Most Amarr/Khanid RPer's draw on existing religions, and that is okay, but it's another thing to portray them as 'Space Catholics' or 'Space Muslims'. There are a couple of problems with this approach:
1) Where ever the Amarr religion has it's roots in the religious landscape as we know it, as Rin said: "Obviously over the many a years since the collapse of the Eve Gate, it evolved into something completely different, and you can't say it's anything mostly resembling to a specific RL religion anymore." The Amarrian religion should be recognised as her very own beast and should be acknowledged and portrayed as such. There is no reason given by PF to assume that the Amarr are 'Space Catholics' or 'Space Muslims' - quite to the contrary. Thus, portraying them as such is going against the PF.
2) Portraying the Amarr as 'Space Catholtics/Muslims' can easily hurt feelings of RL practitioners of those religions. It muddies the waters between fiction and reality and is quite easily leading to debates that cross this border - and that's something that already happens easily enough without portraying the Amarr religion in such a way.
3) It quite easily gets you into conflict with the EVE TOS. As stylizing the Amarr as 'Space Catholics/Muslims' can easily hurt religious feelings - and quite reasonably so, I might add - this can get you quickly into conflict with points 2, 3, and 7 of it. That you are roleplaying is no excuse as is stated in point 4 of the TOS.
So, while it's okay to take RL religions as an inspiration, I'd be careful not to slide into the realm that is caricature or (bad) plagiarization of RL religion. It's not only showing a lack of creativity, it is also unneccesarily taking chances to hurt people.
Typical examples I have seen in my time in EVE of going the 'Amarr are space Catholics' route include, but are not limited to:
- Quoting Biblical Law as 'Scriptural Law'
- Using Christian prayers as Amarrian ones, by simply exchanging "Jesus Christ" with "Dano Gheinok".
- Employing the Psalms as typical Amarrian prayers
These are of course the most blatant things, but it's easy to take a couple of minor things that can easily add up. Of course, there are even weirder things going on, like claiming that Amarr are against science because they are religious.
In my experience most Amarr/Khanid players are thus not only hesitant to call Amarr religion space Catholocism/Islam, but they are quite averse to the idea. If for nothing else, then simply because they don't want to rehash the volatile exchange of opinions that happens IRL (mostly) between Christian Theists (mostly not Catholics, but mainly members of a variety of churches based in the US and in favour of Creationism) and equally evangelical Atheists.