As I remarked to Chris this morning, the tricky thing about historical/cultural writing is that you always have to keep in mind the culture and time period you're writing about, even with your figurative language. E.g., I started to compare something to glass, but had to stop and wonder if Vikings had glass or would know of it. Word choice ends up being dictated as much by cultural authenticity as attempted voice and style. Just makes things a little more complicated. But in a fun sort of way, most of the time.