Gregorio L. Aglipay Day is observed in Batac, Philippines, every September 1 to commemorate the death anniversary of Gregorio L. Aglipay, the first head of the Philippine Independent Church. Aglipay, born in Batac on May 5, 1860, faced early hardships, including being orphaned and experiencing exploitation as a child laborer in tobacco fields. He later studied law and became a priest, actively supporting the Philippine Revolution against American colonization. In 1902, he was appointed as the first Supreme Bishop of the Philippine Independent Church, which aimed to establish a national church free from Spanish influence. The holiday was declared a special non-working day in Batac in 1989 to honor Aglipay's contributions to the country and the church. Celebrations typically involve memorial activities that reflect on his legacy and impact on Philippine history.