Tibaldo and the Hole in the Calendar H/C

Tibaldo Bondi, son of the assistant to the great
Florentine physician Turisanus, is supposed to celebrate
his 12th birthday on October 10, 1582. But 1582 is no
ordinary year. Inaccuracies in the calendar established
under Julius Caesar have been piling up for over a
millennium, the equinoxes are coming earlier and earlier
in the year, and ......