Isabelo de los Reyes (July 7, 1864 – October 10, 1938) also known as Don Belong, was a prominent Filipino politician and labor activist in the 19th and 20th century. He is the founder of the Aglipayan Church and a Forerunner of Filipino Socialism.

Born to Elias de los Reyes and the poetess Leona Florentino in Vigan, Ilocos Sur, he attended schools in Vigan and Manila. He followed his mother's footsteps by initially turning to writing as a career and became a journalist, editor, and publisher in Manila.

Isabelo delos Reyes
(1864-1938)

Last of the propagandists. Gifted son of Leona Florentino, first poetess of the Philippines. Born in Vigan, Ilocos Sur, on July 7, 1864. He aroused the hostility of the friars and government officials when he openly criticized the evils of the Spanish rule and he advocated reforms. He was the founder of the first Philippine labor union, as well as the first independent Filipino Catholic church. Died on October 9, 1938.