Beware of the dog

[1][2] Warning signs of this sort have been found in ancient Roman buildings such as the House of the Tragic Poet in Pompeii, which contains a mosaic with the caption cave canem (pronounced [ˈkäu̯eː ˈkänɛ̃ˑ]).

[3] The Roman work Satyricon, written by Petronius, includes a passage mentioning the phrase cave canem painted on a wall with large letters, in the chapter Dinner with Trimalchio.

[6] Nonetheless, the yard signs are sometimes alluded to in reference to the passage.

[7][8] The use of such signs in the Roman world may have influenced the author of the passage,[9] and conversely the passage may have influenced the wording of the more modern yard signs.

[10] Under English law, placing such a sign does not relieve the owner of responsibility for any harm which may come to people attacked by the dog.