When the Spanish conquistador, Miguel Lopez de Legazpi, who was then based in Panay Island in the Visayas, dispatched, sometime between 1565 to 1570, to this part of the islands an expeditionary force headed by Capitan Luis Enriquez de Guzman, together with their chaplain, the Augustinian friar, Fray Alonso Jimenez, primarily to gather provisions for the starving Spanish force in Panay, and at the same time, evangelize whatever native villages they might come upon in the course of their foray, the group stumbled upon a small fishing village at the mouth of the Ginning River, in what is now the Municipality of Magallanes.

This was the village of Gibalong, the very first Christian settlement in the island of Luzon. It was here where the first mass in Luzon was celebrated by the Augustinian friar, Fray Alonso Jimenez.

Thus, the name Ibalong, to refer to the whole of Bikol Region, really came from this small fishing village, Gibalong, which is now a mere sitio of Barangay Siuton, in Magallanes town, where the local parish constructed sometime in the 1970s a small wooden chapel and a concrete historical marker on the site. In some old Spanish maps, the Spanish cartographers even retained the original spelling by identifying, either the whole Bikol Region or parts of it – Tierra de Gibalong. In his book, From Ibalon to Sorsogon: A Historical Survey of Sorsogon Province to 1905 (New Day Pub. QC, Philippines, 1991), Dr. Luis C. Dery writes, “Historical records showed that the Spaniards started using the name Ibalon as early as 1567 to refer variously to a pre-Spanish native settlement in Sorsogon Gulf, to the entire Bicol Region, and sometimes to the entire island of Luzon. The Spaniards’ indiscriminate use of this name was due to their inadequate knowledge of Bicol geography at the outset of their exploration and conquest of the region. Gradually, they were able to delimit Ibalon and the rest of Kabikolan’s territory.”

Sorsogon became a province, separate from the Province of Albay to which it was formerly attached, in 1894. This is the reason why, in 1994 the centennial foundation anniversary of the Province started to be commemorated and celebrated with a festival – the Kasanggayahan Festival – every October of each year.