The way feudal societies worked, allegiance was like a (bottom up) tree. If your lord was at war with the king you followed the fool. ACOUP has a good number of posts on the workings of feudal societies if you have the time to read them.
Do you know why he was fighting in wars in far away lands? It certainly wasn't about land or power (at least, not for Richard)
It was a Crusade. The 3rd Crusade to be precise.
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Also the whole Reconquista thing in Spain, coinciding with the Spanish Inquisition and all that. Plenty of major religious events that interacted with politics and brought glory to commanders.
And then things like the 30 Years War, which had substantial amounts of religious influence of Protestants vs Catholics.
I'm not saying every war was about religion. But Catholics have PLENTY of holy warriors that are even venerated for their battle prowess.