A patera was a broad and shallow dish or bowl, mostly produced in bronze, and often used as a sacred libation vessel. The ram’s head finial could allude to the ritual function of the object, as the ram was a favoured sacrificial victim at Roman festivals. As well as the religious, the patera was also used in the domestic sphere.
For more information about the meanings of animals in Roman art, see our relevant blog post: Animal Symbolism in Roman Art.