The Penates were deities selected by each family, and frequently by its individual members, as a special protector. Various causes led to this selection. If, for instance, a child were born on the festival of Vesta, it was thought that that deity would henceforward act as its special guardian. If a youth possessed great business talents he adopted Mercury as his tutelary deity; should he, on the other hand, develop a passion for music, Apollo was selected as his patron god, and so forth. These became regarded as the special divinities of the household, small images of them adorned the surroundings of the hearth, and honours similar to those paid to the Lares were accorded to them.
Just as there were public Lares so there were public Penates, which were worshipped by the Roman people under the form of two youthful warriors, who, in later times, were regarded as identical with Castor and Pollux. They are generally represented on horseback, with conical caps on their heads, and bearing long spears in their hands.