In It’s About Time (1935), Gerald Lynton Kaufman tells the fanciful story of sailor Timothy J. McCloskey, who was born on Leap Day 1876 and thus had celebrated only five birthdays when he went to sea in 1896. No leap year was observed in 1900, and he awoke after the night of February 28, 1904, to find that his ship had crossed the international date line in the night, bypassing Leap Day.

Thus he had to wait from February 29, 1896, to February 29, 1908, to advance from his fifth birthday (celebrated at 20 years of age) to his sixth birthday (celebrated at 32).

In Gilbert and Sullivan’s 1879 operetta The Pirates of Penzance, hero Frederic thinks he has completed his pirate apprenticeship at the end of his 21st year — but learns that he was born on February 29 and so must serve another 63 years to reach his “twenty-first birthday.”

How quaint the ways of Paradox!
At common sense she gaily mocks!
Though counting in the usual way,
Years twenty-one I’ve been alive,
Yet reckoning by my natal day,
I am a little boy of five!