This Sunday is the first of Lent, and from hereon in the Office becomes fully Lenten in character liturgically.
This week also features the Lent Ember Days, traditionally days of extra fast and abstinence.
The week in summary in the trad OSB calendar:
Sun 17 Feb First Sunday of Lent, Class I
Mon 18 Feb Monday in the first week of Lent, Class III
Tues 19 Feb Tuesday in the first week of Lent, Class III
Wed 20 Feb Ember Wednesday of Lent, Class II
Thurs 21 Feb Thursday in the first week of Lent, Class III
Fri 22 Feb Ember Friday of Lent, Class II; Chair of St Peter, commemoration
Sat 23 Feb Ember Saturday of Lent, Class II; St Peter Damian OSB, memorial