(LifeSiteNews) — The summer “Ember Days” fall in this week, the week following Pentecost.

For centuries – if not the entire history of the Church – Catholics of the Latin rite have fasted on the Wednesdays, Fridays, and Saturdays of the four “Ember Weeks” in the year.

The four weeks commemorate the changes of season and are intended as opportunities for both penance and the sanctification of time. In particular, the summer Ember Days were linked with thanks giving for the harvest.

These observances are distinctively Roman Catholic. St. Thomas Aquinas wrote that the three “types” of communal fast days in the Roman Church (and Latin rite) are Lent, the Ember Days, and the vigils of certain feasts.

Many authorities believe that they were adopted by the Church in Apostolic times and that some form of this observance probably predates Christianity itself, in both Roman and Jewish tradition.

Although they do not appear in the liturgical calendar in use since the 1960s, they remain in the calendar for the Traditional Latin Mass and were also adopted by the Anglican Ordinariate.

Pope St. Leo the Great encouraged his congregation at Rome to join in the Ember Day fasts with the following words:

[W]e most meetly offer our abstinence to God as a sacrifice of thanksgiving. And what can be more useful than fasting, that exercise by which we draw nigh to God, make a stand against the devil, and overcome the softer enticements of sin?

This same appeal is made to us today.