In Ancient Roman society and everyday life, small bells such as these served many different purposes. They would often have been intended for practical uses such as signalling time, announcements or to keep track of livestock. Bells were also used in some ritual practices, or were hung from tintinnabula, a sort of wind-chime assemblage, designed to ward off evil.
To learn more about everyday bronze items in the Classical World, visit our relevant post: Everyday Items in the Classical World.