Complex sentence: In 1939, Cacoy's elder brother, Eulogio "Yoling" Cañete became president of Doce Pares, the oldest and longest standing martial arts organization in the Philippines and a key contributor behind the popularization of Filipino martial arts.
Split into simpler sentences: In 1939, Cañete's elder brother, Eulogio "Yoling" Cañete, became president of Doce Pares. The organization became the longest-lasting martial arts organization in the Philippines, and was instrumental in the popularization of Filipino martial arts.