The Princess and the Goblin - George Macdonald - Bog

The queen being dead, the princess is looked after by her nurse, Lootie. In reality, there is a much more powerful guardian, her great-great-grandmother, who shares the name Irene with the princess. Princess Irene discovers the old lady at the very top of the castle, but no one else believes in her existence, apart from the king, whose occasional visits punctuate the story. The princess is enchanted by the timeless beauty of the woman, who asks to be referred to as her grandmother, and the two form a bond. The grandmother gives the princess a magic ball of thread with a ring attached. It is to be used, she tells the girl, at times of danger.