October 4th 1582 (Julian) was the day before October 15th 1582 (Gregorian). It was the month when, in Rome, the days shifted from Old Style to New. The bull ‘Inter Gravissimus’ made it so, whatever the many objections of Protestants and Orthodox. It was also, though no one much noticed at the time, the day when, in Alba de Tormes, Teresa of Avila died. Did she die on the night of the fourth or the morning of the fifteenth? And was a child born on the fourth to be named Teresa within the Octave, or one born on the fifteenth?