Abbess Ayesha, formally Novice, was a member of the Sisters of Plenitude.
As a Novice, Ayesha first met the Fourth Doctor and K9 at the Milk Vats of New Savannah. Some sixty years later, she found herself Abbess aboard a spaceship ran by the New New York hospital, researching the human allergies towards cats. There, she ran into the Sixth Doctor and Melanie Bush, who were outraged by the usage of children as test subjects. (PROSE: Fairy Tale of New New York)