As you will all know, we have now come to the end of the ‘gesimas, that pre-Lenten season that includes Sundays with what, to modern ears, sound like wonderfully exotic names from a dim and distant past: Septuagesima (70 or so days before Easter), Sexagesima (60 or so days before Easter) and Quinquagesima (50 days before Easter).
This practice is now unique to those of us who observe the liturgy of the 1662 or 1928 Books of Common Prayer, the Roman Catholic church having dispensed with the practice from 1969. Septuagesima marks the beginning of the Lenten fast. In practice, the clergy wear purple vestments, and the Gloria in excelsis (Glory be to God on high) and the Alleluias before the Gospel are omitted until Easter Day. As a liturgical practice, it is one that originated in the pre-Reformation liturgies of the Roman Catholic Church.
In parts of Italy, there was a tradition of not observing the Lenten fast either on Saturdays or Sundays, hence it left only five days of the week for fasting; in order to make up the forty-day Lenten fast, three more weeks were added prior to the first Sunday in Lent. The inclusion of these Sundays is intended to draw us away from the festive and joyous nature of the Incarnation, celebrated at Christmas and the Sundays following the Epiphany, in order to make a way for the preparation for the penitential Lenten season where the focus shifts to Christ as Saviour and hence to readings which relate to the creation and Fall of mankind.
The design of the Epistles and Gospels [set for these Sundays] is to persuade acts of self-denial and religious duty, and to recommend charity and faith, as the necessary foundation for all religious actions. They follow the old lines [in other words, they are English translations of the Collects included in the Sarum Missal], but the collect for Quinquagesima is a new composition based upon the Epistle and dating from 1549.
It is a tradition that passed into the Anglican liturgical observation after the Reformation through the introduction of the 1549 Book of Common Prayer.
From a musical perspective, this means that, to all intents and purposes, we add three more weeks to Lent. We have re-introduced the plainsong Communion setting, Missa Marialis from The Hymnal 1940, which we sang during the season of Advent. This will be familiar to those of you who attended St. Thomas’ from the 1950s and onwards. It is necessarily more reflective as befits the penitential season. As in previous years, we shall dispense with organ music prior to the start of the service to allow the congregation time for silent reflection; likewise, we shall play a selection of reflective chorale preludes after the services. — Giles Brightwell
 Francis Proctor and Walter Frere: A New History of The Book of Common Prayer With a Rationale for its Offices (London: Macmillan & Co. Ltd, 1955), p. 330, n. 2.
 Ibid., pp. 532f. See n. 1.