Sylvia Agostino is a former student and follower of Arne-Sayles whom Piranesi learns of through entries in his journal. One of Arne-Sayles’s most devoted followers, Sylvia began living with him as an unpaid housekeeper and secretary after graduating college. She was later manipulated into cutting off her parents as a proof of loyalty. A poet, artist, and filmmaker, she produced a number of works during her short life, of which only two, “Moon/Wood” and “Castle,” remain. Both were based—ostensibly—on her visits to other worlds. In 1990, she befriended a doctor named Robert Allstead, but she was instructed by Arne-Sayles to cut ties. She refused and was never seen again. Piranesi believes she is one of the skeletons in the House.