EPONA. As her name implies (epo-, Gallic equivalent of Latin equo-), this goddess was patroness of horses, but also of asses and mules. The majority of inscriptions and images bearing her name have been found in Gaul, Germany and the Danube countries; of the few that occur in Rome most were exhumed on the site of the barracks of the equites singulares, a foreign im perial bodyguard recruited mainly from the Batavians. Her cult does not appear to have been introduced into Rome before imperial times, when she is often called Augusta and invoked on behalf of the emperor and the imperial house. The Romans used to place the image of the goddess, crowned with flowers on festive occasions, in a sort of shrine in the centre of the architrave of the stable. In art she is generally represented seated, with her hand on the head of the accompanying horse or ass.
See articles in Daremberg and Saglio's Dict. des antiquites and Pauly Wissowa's Realencyklopadie.