World War II: Philippine Commonwealth troops under the Philippine Commonwealth Army units enter the province of Ilocos Sur in Northern Luzon and attack invading Japanese Imperial forces.

The Commonwealth of the Philippines was an unincorporated territory and commonwealth (dependency) of the United States that existed from 1935 to 1946. It was established following the Tydings–McDuffie Act to replace the Insular Government of the Philippine Islands and was designed as a transitional…