Whenever January 1, the solemnity of Mary, Mother of God, or August 15, the solemnity of the Assumption, or November 1, the solemnity of All Saints, falls on a Saturday or on a Monday, the precept to attend Mass is abrogated. Also, when December 8th falls on a Sunday, the Solemnity of the Immaculate Conception is transferred to Monday. While the day remains a solemnity, the faithful are not obligated to attend Mass.