I suspect, from your opening paragraph, I know the reason for at least half the agent rejections you have received.
Your first sentence runs to 62 words. it also shifts perspective - jarringly - five times. And all it tells us is "they were killed by men who pray to a different God." Then, within that parapgraph, you pass judgement on the scene and behaviour of your 13th century characters with 21 century sensibilities. You are not giving us the scene from within their heads. You are not colouring it with their justifications.
In effect, you are telling us - not showing us - that we are supposed to hate de Chauvigny. Even though you open the book in his POV. This telling rather than showing persists through the entire excerpt.
Now, I presume from your summary that you are going mostly for a close third person POV, rather than omniscient. Yet, in the second section, you pick up from de Chauvigny's perspective, transitioning part way through to Ralf's.
There are also weaknesses within the dialogue. For example, the line "Your looks have been improved, there are women who prefer their men scarred. Perhaps you should thank the man who marked you." would read better if it were shorter and punchier, more to the point, without the grammatical dressing. Say: "Hmm. An improvement. Maybe it'll earn you a woman. Have you thanked the bastard who marked you?"
That said, your writing generally is decent. You appear to understand the space your action occupies (what can happen in given timeframes,) which is an issue I see with many people's offerings.
If I were going to look to strengthen this piece, I would probably scrap the first half, writing the whole thing from Ralf's very tight POV. Starting away from the masacre, with the urgency to get to it: Time was of the essence… A reference to why he suspects something's amiss, the pressure of distance and heat, then coming upon the scene. And, because you're tight in Ralf's POV, that allows a description of the scene, and a (moralistic) rejection of de Chauvigny's behaviour. It provides a connection between the reader and Ralf, and also sows natural seeds for the reader to hate de Chauvigny.