I realize nationalism is a relatively new concept and that back in the day Saladin would've probably identified himself as a muslim above all, but even so I was wondering about his ethnicity.
I was familiar with the English wiki article about him (bad source I know) in which they say he was of Kurdish ancestry (source were two Kurdish men who lived centuries ago). But I've come across the Dutch wiki page about him and there it says that his ethnicity is disputed. Some (mostly Turkish historians) say that he was a Turk, whereas others say that he was an Arab.
I was wondering whether there is a general consensus on this matter or is this one those things that you can never be sure about?
And did his ethnicity play any role for him (or his contemporaries) or was it really just a matter of his religious beliefs?
Thank you.
An idea that one is just so clearly one ethnicity is fairly modern. Depending on language, people will claim he's a variety of ethnicities (Kurdish, Arab, Turkish). See here for an earlier time this question was answered. As you know, the status that really mattered to his world was his religion (Sunni Muslim, rather than Greek or Latin or Armenian or Syriac Christian, or even Fatamid possibly Shi'a-ish Muslim), rather than ethnicity which is a much more meaningful division since the rise of nationalism especially after the 18th and 19th centuries. Sub-national boundaries that we rarely think of, like clan or tribe, were also meaningful in this period, but such as pre-modern ethno-linguistic boundaries existed (in an age before writing even standardized dialects into language, and the nation state standardized the belief that everyone is a member of one ethnically defined nation from birth), they were both notably blurry and porous. It just wasn't a particularly relevant social category (not that it was totally irrelevant, just that it wasn't a primary meaning).
It's not the perfect analogy, but the one that comes to mind is what type of Protestant someone is in the mid-20th century America. It mattered that some are Methodist and some are Lutheran, but some people go to multiple churches, some rarely went to church, and some people's actions were clearly not so defined by their formal affiliations (Hoover and Nixon were both Quakers, if you can believe it). Ethnicity seemed to matter relatively little for elite marriages in this period, and I am not an expert on other social classes from this period, but it appears while religious endogomy was common, I don't remember any references to ethnic endogomy independent of religion, which I think hints at its (relative lack of) importance.
I can't speak to Saladin's ethnic background, but I've read Bahā' al-Dīn's biography of Saladin and can speak a bit to your last question. Bahā' al-Dīn, who was Kurdish himself, was an advisor and close friend of the man. He wrote extensively on Saladin's military prowess, leadership skills, noble character and general "Best Muslim Ever"ness in terms of holding to the five pillars of Islam. Bahā' al-Dīn took care to present a lot of personal anecdotes regarding the latter, and much of Saladin's actions in the wider world points to a man heavily invested in his faith and identity as a Muslim.
Imād al-Din and Ibn al-Athir, also contemporaries of Saladin, wrote eyewitness accounts of his feats before and throughout the Third Crusade that hold much the same praise, though in varying degrees of enthusiasm. I hope this helps!