Sister Catherine (formerly known as Catherine Vertue, then Catherine Norrington and to become Mother Athanasius) is a character appearing in the episode A Sacred Trust of the ITV crime drama Midsomer Murders.
Catherine Norrington was the first novitiate at the Order of St. Mathilde for thirty years. At the time of the episode she had not yet taken her final vows and her parents, George and Delia, wanted her to delay doing so. But she'd been in the convent for three years and claimed it was the happiest she had ever been.
Catherine's surname, before she was adopted by her step-father, George Norrington was Vertue, the same as the village, and the pub. That made her the Vertue heir, and that if the community did not survive, she would inherit all the property and buildings. Catherine, however, declared that it was not at all important, because it would survive. She would see to it. Her mother and stepfather did not know, she found out her legal position by chance, when doing research for her PhD.