What is the name of this series?

I can't remember the name of this series, and I'd like to read it again. It is a fantasy type series, with 4 or 5 books. It is sort of like time travel, with characters going to another world that is much like Italy in the 1500s. The first character uses a notebook, the second a figurine of a winged horse. The first character's name is something like Lucan, or Lucien. The second's is Georgia, and that's all I really remember right now.