Maximiliana Sebastiane (Max) Horne is a major character in Madeleine L'Engle's novel A House Like a Lotus (1984, ). A friend of Sandy Murry, she befriends and mentors Polly O'Keefe.
Max is a wealthy intellectual and a painter whose work hangs in museums and private collections. Although she was once married, Max has lived for more than 30 years in a happy lesbian relationship with neurosurgeon Dr. Ursula Heschel. Engaging and energetic, Max befriends and mentors Polly, and they become close friends despite the significant difference in their ages. Max is lean and elegant, with black hair and silver-grey eyes. She has a keen interest in a wide variety of subjects including anthropology, theology, and literature and is a lively conversationalist. In the course of her many travels throughout the world, Max was bitten on the eyelid during a trip to South America and contracted Netson's Disease, for which there is no cure.
Max and her younger sister Minerva Allaire ("M.A.") were raised at Beau Allaire, a plantation Max inherits through her mother's family. Their mother dies when Max and M.A. are young girls, and they grow up dominated by a ruthless, physically and emotionally abusive father who Max describes as a "lecherous old rogue." One night when Max is away, he attempts to rape M.A.. She manages to get away from him, but runs into the rain, catches pneumonia and dies in anguish. Max never forgives him, but keeps his portrait in Beau Allaire's dining room to remind herself never to be like him.
As a young woman, Max marries Davin Tomassi, a colleague of Sandy Murry. Max gives birth to a daughter who dies a few days later, breaking Max's heart. Max and Tomassi divorce. After a series of indiscriminate affairs, Max meets neurosurgeon Ursula Heschel, and they enter into a loving relationship. In A House Like a Lotus, they have been lovers and confidantes for more than 30 years.
Max is a successful painter, and some of her paintings are displayed in museums and private collections. A collector of art, she displays works by Hogarth, Van Gogh, Pissarro, and Picasso in Beau Allaire. One of her show pieces is a sculpture known as the Laughing Christ of Baki; this becomes Polly's favorite work, and she and Max talk about it often.
Max and Ursula, who usually live in New York City, have come home to Beau Allaire because of Max's urgent need for medical treatment. On a trip to South America, Max contracted the fatal Netson's disease which kills by parasites invading the heart. There is no cure. A distant cousin of Max's is the world's leading specialist in this disease, and he is on the staff of M.A. Horne Hospital, founded by her father after M.A.'s death. In short, Max has come home to die.