Who is Jessica from The Lion's Lady and what is their importance?

Jessica is Christina's birth mother. She is also the woman who nursed White Eagle back to health after he was beaten by a rival tribe. Once married to a king, Jessica had run away because of her husband's cruelty. She and Merry spend a year in the wilderness together and Christina was killed by a bear on the day before the women had planned to depart their winter camp. It was generally accepted that Jessica was "weak minded" although Christina did not think so.