Ancient Mystical Order Rosae Crucis, they claim to be the Rosicrucian Brotherhood. Although most Rosicrucians date themselves to early 17th century manifestos, AMORC claims to go back to Pharaoh Thutmose III of Egypt circa 1500 b.c.e. The order itself was founded in the US by Harvey Spencer Lewis (1883–1939), who had worked in advertising as an illustrator. Around 1915, Lewis hit upon the idea of marketing AMORC via mail order, and their ubiquitous advertisements appeared in numerous popular magazines. The organization began in New York City, but in 1918 the police raided them and Lewis was arrested for selling fraudulent books and collecting money under false pretenses. Charges were dropped, but Lewis moved the Order to San Francisco and then Tampa, Florida. In 1927 AMORC moved to San Jose, California, and incorporated as a religion. This was abandoned after a few years and the fraternal nature of the Order was stressed. In San Jose they created Rosicrucian Park, including faux Egyptian buildings, a museum, and the fifth planetarium built in the USA (and still in use today). Teachings seem very similar to “New Thought,” the mystical system that evolved out of late 18th-century Spiritualism.

Upon his death, leadership of the order switched to his son, Ralph Maxwell Lewis (1904–1987). After Ralph's death a new leader was selected, but shortly afterward he was fired, the Order was reorganized, and the Supreme Grand Lodge moved to Quebec, Canada.

AMORC has worked hard to support their claim to being the true Rosicrucian Order. In the past they have fought other groups over this, including taking R. Swinburne Clymer and his Fraternitas Rosae Crucis to court, where each claimed the other practiced black magic. At one time, Aleister Crowley made a weak attempt to take over AMORC.