What is the Wheel of Fortune, and how is it significant to Boethius?

Lady Philosophy explains that the vagaries of Fortune visit everyone, and he is by no means the worst of her victims. Even though he is imprisoned and due for execution, he has still the faculties of his mind and soul to comfort him. She explains that the gifts of Fortune were never his at all, but merely lent to him and taken away as easily as they were given. Health, wealth, honor, and power are things that never truly belong to any human being, and are visited on them by the wheel of fortune and quickly snatched away. Therefore it is unwise to become attached to any temporal thing.