This could have been a very good book - the bones of the historical story are good, and the characters, particularly the female ones, interesting and sympathetic.
Unfortunately the time-shift element just didn't work for me - as is often the case, one story was much more compelling than the other, and the change from the past to the modern-day interrupted the flow. It lost me a little in the middle as well, as the story seemed to meander.
I might read something by this author again, but I'd want it to be much more tightly written.