Check out the oldest known “Beware of Dog” sign, is this briliantly preserved tile mosaic from Pompeii which features an illustration of a dog and the words “Cave Canem” which translates to “caveat” (beware) and “canine” (dog).
The mosaic is at the House of the Tragic Poet, a Roman house in Pompeii, Italy dating back to the 2nd century BC. The house is known for its elaborate mosaic floors and frescoes showing scenes from Greek mythology. [source]
It was found in November 1824 by the archaeologist Antonio Bonucci, the House of the Tragic Poet has fascinatedscholars and writers for generations. Although the size of the house itself is in no way exceptional, its interior furnishingsare not only numerous but of the highest quality among other frescoes and mosaics from Pompeii. Because of the mismatch between the size of the house and the quality of its items, much has been questionedabout the lives of the homeowners. Sadly, not much is known about the family members, who were likely killed by the eruption of Mount Vesuvius in 79 AD. [source]