The ancient Egyptians believed that each individual was comprised of five distinct aspects. Among these was the Ba, corresponding roughly to our notion of personality. In order for the physical body of the deceased to survive, it was necessary that it be able to reunite with its Ba in the form of a bird. A figure of the Ba was often placed upon the chest of the mummy. This funerary practice was especially prevalent in the Late Dynastic and Ptolemaic Periods.