The Latin phrase sub rosa means "under the rose" and is used in English to denote secrecy or confidentiality, similar to the Chatham House Rule.
The rose was the emblem of the god Horus in ancient Egypt. Later, the Greeks and Romans translated the god's Egyptian name Har-pa-khered as Harpocrates and regarded him as the god of silence. The association of Harpocrates with silence and secrecy originates from a misunderstanding of Egyptian depictions of the god. Heru-pa-khered was represented as a naked youth with a finger-to-mouth gesture--in Egyptian artwork this gesture imitates the hieroglyph for child and is used to represent youth, but was misunderstood by later Greeks and Romans as a gesture for silence.
The rose's connotation of secrecy dates back also to Greek mythology. Aphrodite gave a rose to her son Eros, the god of love; he, in turn, gave it to Harpocrates, the god of silence, to ensure that his mother's indiscretions (or those of the gods in general, in other accounts) were not disclosed. Paintings of roses on the ceilings of Roman banquet rooms were also a reminder that things said under the influence of wine (sub vino) should also remain sub rosa.[1] In the Middle Ages a rose suspended from the ceiling of a council chamber similarly pledged all present (those under the rose) to secrecy.[2]
In Christian symbolism, the phrase "sub rosa" has a special place in confessions. Pictures of five-petalled roses were often carved on confessionals, indicating that the conversations would remain secret. The phrase has also been understood to make reference to the mysterious virginal conception of Christ.
In the 16th century, the symbol of Henry Vlll of England was the stylised Tudor rose. A large image of the rose covered the ceiling of the private chamber where decisions of state were made - in secret.
In current times, the term is used by the Scottish Government for a specific series of "off the record" meetings.[2]
More recently, "sub rosa" activities have become a byword for covert operations, usually by security services. Originating primarily in the Canadian and American special forces, this meaning has been gradually spreading to other countries and in particular the United Kingdom. To refer to covert operations, the Special Boat Service uses the term in the vernacular.
For many Hungarians, the expression "sub rosa" originates from the time of Wesselényi conspiracy in 1670. According to the legend, the conspirators organised their meetings in a secluded small balcony room in the Rákóczi castle at Sárospatak. In the middle of the painted ceiling there is a rose. While in reality it was probably just a pun, using both the literal "under the rose" meaning of "sub rose" as well as its reference to secrecy, many Hungarians believe that the latter meaning of the expression originated from the conspiracy, which, in fact, is known as the "Sub-rosa conspiracy" in Hungary.