Saturday, October 15, 2016

Feast of St. Teresa of Avila & a Calendar Change

Peter Paul Rubens 138.jpg
St. Teresa by Peter Paul Rubens.

Today is the Feast of St. Teresa of Avila (+1582AD), the Spanish Carmelite and Doctor of the Church.

St. Teresa was born in Avila, in the Kingdom of Castile and Leon, and joined the Convent of St. Mary of Mt. Carmel in her late teens.  She struggled with poor health much of her life, but it didn't stop her from being both a great reformer of the Carmelite Order, and a magnificent author of works on mystical Theology.

You can read more about her life at the sites:

Catholic Saints Info: St. Teresa of Avila

Old Catholic Encyclopedia: St. Teresa of Avila

An interesting side note is that while she died on 4 October 1582 AD, her feast is kept on 15 October, which was the day after her death that night of the 4th.  It was the very night that St. Teresa of Avila died that the new Gregorian Calendar of Pope Gregory XIII replaced the Julian Calendar.  Not only did the Catholic world adopt this calendar with its different, more accurate, determination of leap years, but it also shift the date to offset the margin of error of the Julian Calendar, resulting in dropping 10 days from the calendar.  This meant that 4 October 1582 was followed by 15 October 1582 with the days in between simply omitted!

Of course, the non-Catholic world took some time to adopt this more accurate, but papal decreed, calendar.  Somewhat famously, Great Britain and her colonies finally adopted it in 1752, along with the 1 January start to the year.  In the English-speaking world 2 September 1752 was followed by 14 September 1752, as, by that time, 11 days were needed to correct the Julian Calendar error, instead of 10 (it would be 13 in 2012AD).  Those English dates before the changeover that were reckoned by the Julian Calendar are referred to as O.S. "old style" in some sources.  Before England adopted the Gregorian Calendar, while a person in Paris might consider it 21 March 1605, the same day in London would be considered 11 March 1604 (O.S.).

The root of the Julian Calendar error is this: it presumed that the year was 365.25 days long, meaning that a leap year every four years would account for the decimal places and keep the calendar year in sync with the actual solar year.  As it happens, the year is more precisely 365.2422 days long, meaning that the seasons would slowly drift away from their calendar dates with the Julian Calendar -- for instance, by 1582, the Vernal Equinox was occurring on 11 March, rather than 21 March as is traditionally assumed.  So, the new Gregorian Calendar restored the Equinox to its traditional date by dropping 10 days that October of 1582.  It would try to remain accurate by modifying the reckoning of leap years: it would  have a leap year every year divisible by 4, except those divisible by 100 (most years such as 1700AD are not leap years), but if divisible by 400, remaining a leap year (so 1600AD was a leap year).  This is still a hair off, and some have suggested that we waive the leap year in 4000AD to fix the problem.

So, on this feast of a Catholic Doctor of the Church, we might recall, too, that the very calendar that tells us that it is 15 October 2016, was instituted by a Pope, and took effect the year of St. Teresa's death: 1582.

Live well!

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