For many early Christians it was the beginning of the fast before Easter...For some, Quinquagesima marked the time after which meat was forbidden ...Where abstinence from meat began earlier, this Sunday introduced the time in which neither milk nor eggs etc, (ova et lacticinia) were allowed...In many places this Sunday and the next two days were used to prepare for Lent by a good confession; hence in England we find the names Shrove Sunday and Shrovetide.
Since I discovered the traditional Mass two years ago I have enjoyed learning and experiencing the richness of the traditions of the Church, developed over centuries, that seem to have been so carelessly cast aside in the last 40 years. I remember at my old parish how Lent would almost always sneak up on me, and on Ash Wednesday I had not given serious reflection to what I would "do" for Lent. I would often just choose some privation, sometimes a token one, without any reflection and without any plan or purpose.
In the traditional calendar, Lent doesn't sneak up on you. The Church establishes three consecutive Sundays-- Septuagesima, Sexagesima, and Quinquagesima, roughly and symbolically corresponding to periods of 70, 60, and 50 days before Easter. Those Sundays are penitential Sundays that don't affect the feast days during the week, but are a nice spiritual transition from the intense joy of Christmas to the desert of Lent.
It makes you wonder why it was jettisoned.
Again, from the Catholic Encyclopedia:
As the days before Lent were frequently spent in merry-making, Benedict XIV by the Constitution "Inter Cetera" (1 Jan., 1748) introduced a kind of Forty Hours' Devotion to keep the faithful from dangerous amusements and to make some reparation for sins committed.
To that end, check out the Forty Hours Devotion Schedule at St. Francis de Sales. http://www.institute-christ-king.org/documents/40Hours2007.pdf
Have a blessed and spiritually profitable Lent. Let us never forget to pray for the Holy Father.