This document discusses the debate around the site of the first Catholic mass in the Philippines between Limasawa Island in Southern Leyte and Masao in Butuan City. It provides evidence from historical accounts and documents that support both locations. Key details include Pigafetta's journal mentioning Mazaua, which is believed to be Limasawa, and monuments erected in Butuan commemorating the site. After reviewing the primary records and geographical details, the conclusion is that the first mass was most likely held on March 31, 1521 in Limasawa Island, as declared by the National Historical Institute and Philippine Congress.