Beware of Dog! A 2,000-Year-Old Warning From Pompeii

Today, “Beware of Dog” signs are fixtures on fences around the world. These notices, which have been printed in languages ranging from Latvian to Japanese, make it clear that a menacing mutt is on the premises.

These simple signs actually date back thousands of years. Some of the oldest examples come from the Roman city of Pompeii, which was buried under volcanic ash in A.D. 79. In 1824, archaeologists excavating the ruins of a Pompeiian house discovered an intricate mosaic depicting a snarling black dog sporting a spiked collar and chain.

In between the pet’s paws reads the Latin phrase “CAVE CANEM”: Beware of Dog.

It should be no surprise that ancient Romans had a soft spot for canines. Legend has it that a she-wolf nurtured Rome’s founder Romulus and his twin brother Remus.

As the civilization expanded, ancient Romans adopted breeds from throughout Italy and imported varieties from Britain and Greece. These ranged from the bruising, mastiff-like Molossian to the tiny, white precursors to modern Malteses.

Ancient Romans relied on dogs for several purposes, including hunting, racing and companionship. One of their main roles was to guard homes, businesses and livestock. The poet Virgil wrote that “never with them on guard need you fear for your stalls a midnight thief, or onslaught of wolves.”

The ideal Roman guard dog was big with a deep bark. Darker dogs, like those depicted in the Pompeii murals, were ideal for protecting the home. According to Roman writer Columella, black dogs “terrify thieves in the daytime and [are] less visible to trespassers at night.”

The ‘Cave Canem’ sign graces the entryway of what is now known as the House of the Tragic Poet, a dramatic domicile with walls plastered in frescoes. Several other homes in Pompeii displayed similar mosaics of chained canines near the front door. Many of these guard dogs perished alongside their owners when Vesuvius erupted. In one house, archaeologists discovered the imprint of a doomed dog, its body still contorted in a futile attempt to escape its collar.

Due to the prevalence of prowling guard dogs, it’s likely that ‘Cave Canem’ signs were widespread in the Roman world. These notices are even featured in the era’s literature. One work, Petronius’s satirical Satyricon novel from the 1st century, mentions that a character’s home has “an enormous dog upon a chain was painted upon the wall, and above him this inscription, in capitals: BEWARE THE DOG.”

The signs appear to have inspired other writers. A few decades before the eruption of Mount Vesuvius, the Christian apostle Paul urged followers in the Greek city Philipi to avoid evildoers by using the phrase “beware of dogs.” Paul’s letters to the Philippians became part of the Christian Bible’s New Testament.