Sexagesima is today, February 12:
More on this pre-Lent season called Septuagesima here, from Amy Welborn.
And if you want to do a deep-dive, read the section from the great liturgical scholar Dom Guéranger
In order to console us in the midst of the combats, which so thickly beset our path, the Church, – like a beacon shining amidst the darkness of this our earthly abode, – shows us another Seven, which is to succeed the one we are now preparing to pass through. After the Septuagesima of mourning, we shall have the bright Easter with its Seven weeks of gladness, foreshadowing the happiness and bliss of Heaven. After having fasted with our Jesus, and suffered with him, the day will come when we shall rise together with him, and our hearts shall follow him to the highest heavens, and then after a brief interval, we shall feel descending upon us the Holy Ghost, with his Seven Gifts. The celebration of all these wondrous joys will take us Seven weeks, as the great Liturgists observe in their interpretation of the Rites of the Church:- the seven joyous weeks from Easter to Pentecost will not be too long for the future glad Mysteries, which, after all, will be but figures of a still gladder future, the future of eternity.
Having heard these sweet whisperings of hope, let us now bravely face the realities brought before us by our dear Mother the Church. We are sojourners upon this earth; we are exiles and captives in Babylon, that city which plots our ruin. If we love our country, – if we long to return to it, – we must be proof against the lying allurements of this strange land, and refuse the cup she proffers us, and with which she maddens so many of our fellow captives. She invites us to join in her feasts and her songs; but we must unstring our harps, and hang them on the willows that grow on her river’s bank, till the signal be given for our return to Jerusalem [Ps. cxxv]. She will ask us to sing to her the melodies of our dear Sion: but, how shall we, who are so far from home, have heart to sing the Song of the Lord in a strange Land? [Ps. cxxxvi]. No, – there must be no sign that we are content to be in bondage, or we shall deserve to be slaves for ever.
