<P> A person born on February 29 may be called a "leapling" or a "leaper". In common years they usually celebrate their birthdays on February 28 . In some situations, March 1 is used as the birthday in a non-leap year since it is the day following February 28 . </P> <P> Technically, a leapling will have fewer birthday anniversaries than their age in years . This phenomenon is exploited when a person claims to be only a quarter of their actual age, by counting their leap - year birthday anniversaries only . In Gilbert and Sullivan's 1879 comic opera The Pirates of Penzance, Frederic the pirate apprentice discovers that he is bound to serve the pirates until his 21st birthday rather than until his 21st year . </P> <P> For legal purposes, legal birthdays depend on how local laws count time intervals . </P> <P> According to Herodotus (5th century BC), of all the days in the year, the one which the Persians celebrate most is their birthday . It was customary to have the board furnished on that day with an ampler supply than common: the richer people eat wholly baked cow, horse, camel, or donkey, while the poorer classes use instead the smaller kinds of cattle . </P>

Where does the tradition of celebrating birthdays come from