Simbang Gabi is one of the longest and most popular religious traditions in the Philippines. For nearly four decades, Simbang Gabi has been a cherished part of the rich religious and cultural traditions of the Archdiocese of Los Angeles. Simbang Gabi, Misa de Gallo (Rooster’s Mass) or Dawn Masses is a nine-day novena to the Blessed Virgin Mary, the Expectant Mother of God. Simbang Gabi Masses in the Archdiocese of Los Angeles adhere to the liturgical guidelines appropriate to the Season of Advent.