NY: Ballantine, 1992.
I read this above-average alternate history novel when it was first published and I was impressed. I knew who the author was via his several earlier Byzantine-themed stories, which I thought were pretty good (possibly because I had some background in the history of that period), but this was his first novel in a comparatively modern setting. It was also, I believe, his first real commercial success. Unfortunately, it kind of went to his head.