João Maria D'Agostini, or Giovanni Maria de Agostini (1801 – 17 April 1869), was a lay monk of Italian origin who travelled widely in South and North America preaching and healing with herbal remedies.He drew large crowds who believed that he was a holy man who could work miracles, although the authorities often viewed him with suspicion. In Brazil his devotees have conflated his identity with two other monks named João Maria.Thousands people each year visit a cave in the state of Paraná, Brazil, where he once lived.