De Witt, Elfrieda: - When introduced to her art, Michael Brown immediately knew that Elfrieda De Witt would be the perfect choice of collaborator for his Santa Mouse stories. Her style perfectly captured the spirit of Christmas. Known affectionately as Freddie by friends and family, Elfrieda spent much of her career illustrating for greeting card companies. Brown and De Witt continued their friendship for many years after the publication of the Santa Mouse books.