In his 1618 pamphlet, Pia et Utilissima Admonitio de Fratribus Rosae Crucis, Henrichus Neuhusius wrote that the Rosicrucians departed for the east due to European instability caused by the start of the Thirty Years' War. In 1710, Sigmund Richter, founder of the secret society of the Golden and Rosy Cross, also suggested the Rosicrucians had migrated eastward. In the first half of the 20th century, René Guénon, a researcher of the occult, presented this same idea in some of his works.[16] An eminent author of the 19th century, Arthur Edward Waite, presented arguments contradicting this idea.[17] It was in this fertile field of discourse that many Rosicrucian societies arose.