The seventeen-day period prior to Lent is referenced here, as is that prime penitential season:
157. During the days of Septuagesima and Lent, our Holy Mother the Church over and over again strives to make each of us seriously consider our misery, so that we may be urged to a practical emendation of our lives, detest our sins heartily and expiate them by prayer and penance. For constant prayer and penance done for past sins obtain for us divine help, without which every work of ours is useless and unavailing.
And Holy Week also has its focus:
158. In Holy Week, when the most bitter sufferings of Jesus Christ are put before us by the liturgy, the Church invites us to come to Calvary and follow in the blood-stained footsteps of the divine Redeemer, to carry the cross willingly with Him, to reproduce in our own hearts His spirit of expiation and atonement, and to die together with Him.
Union with Christ: a theme visited often in the pages of Mediator Dei, continues to be the focus of these weeks before Easter.
Catholic Sensibility 