Bernard Cornwall

It's more complex than that. Arthur is not anti-Christian, he's all for peace between religions. The title of the second book, "Enemy of God", hints at the "title" given him by a few Christian fanatics and hypocrites he rubs the wrong way and who give him a bad name out of political rather than religious motives. In addition to that, Cornwell's work is based in a historical setting, ca. 500AD, well before the literary traditions that portray Arthur as a Christian king (although there's also quite a bit of literature that does not portray him as that, including in Welsh sources). Considering what we know of Christianity in the Isle of Britain in that age, it makes sense that many different religions are portrayed in the story, not just Christianity, and that Arthur is a less straightforward Christian than he appears in the literature of the later Middle Ages. There are quite a few insufferable Christians in the Warlord Chronicles, which may give some readers the overall impression that the author himself is anti-Christian. But when you read more carefully, you realize there are quite a few insufferable anythings, not just Christians! Arthur's enemies are fanatics, and they come in all shapes and colours. There are also a few good, honorable men, and these also follow different religions. It is one of the things I loved and found most interesting in his work, as opposed, for example, to the work of Marion Zimmer Bradley and her manichean Christian-bad/Pagan-good narrative (or Lawhead's Pagan-bad/Christian-good story, for that matter).

I haven't read Jack Whyte's work so thank you for the suggestion!

"Occasionally I'm callous and strange."