Monday after Pentecost
The Blessed Virgin Mary, Mother of the Church
“Having attentively considered how greatly the promotion of this devotion might encourage the growth of the maternal sense of the Church in the pastors, religious and faithful, as well as a growth of genuine Marian piety, Pope Francis has decreed that the Memorial of the Blessed Virgin Mary, Mother of the Church, should be inscribed in the Roman Calendar on the Monday after Pentecost and be now celebrated every year.
This celebration will help us to remember that growth in the Christian life must be anchored to the Mystery of the Cross, to the oblation of Christ in the Eucharistic Banquet and to the Mother of the Redeemer and Mother of the Redeemed, the Virgin who makes her offering to God.” 
 From the Decree on the celebration of the Blessed Virgin Mary Mother of the Church in the General Roman Calendar, for the full text see press.vatican.va