September 13 is the anniversary of The Battle of Pulang Lupa in 1900. This battle was a part of the Philippine-American war, where The Philippines sought to gain independence from the US.

An imperialist unit was searching for Colonel Maximo Abad, who was leading the Filipino resistance forces. Abad had good information on their movements, and planned an ambush. They killed 4 American soldiers, and took the remaining troops prisoner.

In retaliation for this defeat, the American invaders issued this order:

Treat the entire male population over fifteen as potential enemies and to arrest as many as possible and hold them as hostages.

In a terrorism campaign that would echo often in the US regime, they rounded up much of the civilian population and placed them in concentration camps. They burned villages and farms, and they inflicted as much pain and suffering on the civilian population as they could in the hopes that the people would turn on Abad. It worked this time.