Shrove Tuesday when traditionally pancakes are eaten to use up all the fat in the house, prior to the beginning of Lent which starts the following day, Ash Wednesday. Lent was seen by Christians as a time of penitence and self-denial.
But – According to Wiki “The Ancient Greeks made pancakes called τηγανίτης (tēganitēs), ταγηνίτης (tagēnitēs) or ταγηνίας (tagēnias), all words deriving from τάγηνον (tagēnon), “frying pan”. The earliest attested references on tagenias are in the works of the 5th century BC poets Cratinus and Magnes”.
“…. another invention of Pagans that Christianity gobbled up with syrup on top.” (Garry Otton)