If you don't know this piece, well its ok...it isn't widely known although it should be. You won't go away humming it either. Just take a minute sometime today and relax to it. Matins is part of the church day and said at night...lauds at sunrise, matins at night...that's what I remember anyway and being Lutheran, well, I get stuff in the catholic liturgical cycles pretty mixed up...anyway. just enjoy it and put yourself at peace.