The poem describes the Countess Cathleen after her death. She has left behind the raiment and pride of her worldly existence and walks with mournful beauty. She dances among the angels and all the universe in in accord with Heaven.
The Countess Cathleen is a figure out of Irish legend. Yeats later wrote a play about her, in fact. According to her legend, a famine strikes Ireland and Satan sends demons to buy the souls of the starving Irish. The Countess sells her vast estates and possessions in order to purchase the people food and to keep them from selling their souls. She is thwarted by Satan, however, and eventually sacrifices her own life for the Irish poor.
The Countess' legendary donation of her worldly possessions takes on an otherworldly aspect in this poem. It suggests that Cathleen, in giving over her body, lets go of her heavy burden. She dances lightly and wisely in the heavens, celebrating her sacrifice and her role in the grand order of the universe.