The Spanish Pearl by Catherine Friend is a historical fiction novel in which the main character is somehow transported from modern day Spain to 1085 in the same location.
Kate Vincent and her girlfriend Anna are in Spain to adopt a son. Due to him having a fever they cannot take him from the orphanage yet. So on their free day they have to decided what sites to see.
Anna, a history scholar, wants to see the Palace that is now a museum. But after a quick walk around, Kate wants to see the cave Mirabueno that their soon-to-be son thinks is great. A man at the museum warns Kate that the cave is not safe, but she goes anyway.
During the group tour of the cave, an ankle injury causes Kate to fall behind. She decided to cross the rope barrier to sit on an obvious shelf until the tour returns.
What feels like hours later, she wakes up in a totally dark cave. The lights and guide ropes are gone. When she goes outside, the city of Zaragoza is also missing. Only the Palace remains on the horizon.
Kate is back in the time that her girlfriend studies. The time to El Picador , El Cid and the wars between Moors and Christians for control of Spain. Friend has thrown in a twist that makes this a great read in what could become a terrible situation for any woman, but a lesbian maybe even more. At a painter, Kate has a still that just might keep her from being married off to the first man who asks.
Friend, Catherine. (2007). The Spanish Pearl. NY: Bold Strokes Books.