A Simbang Gabi is a nine-day Roman Catholic ritual novena performed in the Philippines which starts from December 16 and ends on December 24. Simbang Gabi, which translates to Evening Mass is usually performed as early as 4 or 5 in the morning. The last day of the Simbang Gabi, which is Christmas Eve, is called Misa de Gallo, which literally translates to “Rooster’s Mass”
The Simbang Gabi originated not just out of devotion, but also due to practicality. In the 333 years that Spain ruled the Philippines, it was customary for the friars and priests (known then as frailes y cura parrocos) to celebrate Holy Mass for the multitudes of Filipinos living in the barrios. In less than two generations after the arrival of the Spaniards, or by 1600, the greater part of the islands have been successfully converted to the Catholic faith.
Simbang Gabi starts so early because of the experience of the Filipinos under the Spanish Regime.