When characters surprise you

So, while I'm shopping around for an agent who might be interested in the first book of my series, I became caught up in the excitement of starting the second book. However, as I began writing, my protagonist surprised me by demanding that some of her past and her beliefs be quite different than I had originally conceived! This has sent me on a research intensive because I want to get to know her in more depth and understand what drives her before I get too far into the manuscript.

Part of my research into her belief system involves Saint Hildegard of Bingen, a 12th Century Abbess in Germany. Who knew?!