Expectation of the Blessed Virgin Mary

Article

This is a memorial to impress on the faithful the sentiments of the Blessed Virgin as the time of her delivery approached.

The feast originated in Spain. When the feast of the Annunciation (25 March) was transferred to 18 December because of the regulation forbidding feasts in Lent, it remained on this date after the Annunciation was again celebrated on its original date.

Source: https://catholicsaints.info/expectation-of-the-blessed-virgin-mary/