The history of Baao dates back to pre-Hispanic times, and got its name from “Ka-baoo-wan” or “ba-oo”, the local term for freshwater turtles. It is said that the turtles abound in the wetlands and swampy grounds of the early neighboring settlements, and nested in the drier upland areas of what is now known as Baao.

The first mention of Bao (as it was known then) in historical records was in 1576 when its inhabitants together with those from Bula, and Naga resisted the Spanish colonizers when they sat foot in this part of the Bicol peninsula. Bao was thus only a barrio attached to Bula in the early 16th century.

Fr. Peter Baptist, who was to become a Saint eventually, officially founded Bao as a village in 1590. The following year, the village of Bao was mentioned in the census as an encomienda and a visita of Bua (Nabua). The census counted 704 people living in the village.

In 1771, after almost two centuries, Bao becomes independent of Bula becoming a separate church-administered territory by Fr. Jose de Maria.

In 1773, Bao becomes embroiled in territorial dispute with Nabua when the inhabitants of Bao captured a group of fishermen from Nabua. Local authorities coming from Naga arrived to settle the dispute.

The number of people living in the village jumped to about 1,900 families in 1792. The year after, Baao had its first parish priest in the person of Fr. Domingo de Palencia. With this, Baao officially became a ‘pueblo’ or town independent of Bula. It was also assumed that it was at this point that ‘Bao’ was changed to Baao as the name of the town.

Dispute with the town of Nabua arose again in 1806 when a group of Baao residents were accused of cattle-rustling and detained by Nabua residents. Two years later, the trouble with Nabua erupts to a full-blown conflict because of a territorial boundary dispute. Many people from both towns, including members of wealthy landed families, were killed. The provincial government had to step in but the dispute remained unresolved for many years.

It was in 1849 that the people of Baao started replacing their surnames into names which start with the letter ’B’ upon the decree of Governor-General Narciso Claveria. Today, one will find most residents of Baao to have surnames that start with the letter ‘B’.

In 1888, some members of the Baao principalia were implicated in the Propaganda Movement after a member of the guardia civil reported to his ‘comandante’ based in Iriga that subversive materials were circulated by the group in the town.

The 1900’s

After the declaration of Philippine independence by Pres. Emilio Aguinaldo in 1898, Don Paulino Bernas was appointed to serve as ‘alcalde’. In February 25, 1900, the famous Battle of Agdangan was fought by Bicolanos which included soldiers, and volunteers from Baao, and other towns of Rinconada against a superior force of several American companies. Although defeated, the Baaoenos, and other soldiers from Rinconada distinguished themselves admirably against the Americans.

When the Americans finally took control, they appointed Don Fulgencio Sanchez as ‘alcalde’, and in June of 1901, Baao had its first elections for the position of ‘alcalde’, and ‘tiniente alcalde’.

From 1901 until 1940, Baao enjoyed a period of tranquil peace. This was to be broken by the Japanese invasion, and occupation which resulted to great loss of lives and property. Japanese forces were first sighted in Baao in December 14, 1941, and from that day forth, Baaoenos had to endure more than 3 years of suffering from Japanese occupation. In April 15, advance forces of the Americans reached Baao, and on April 29 when the main body of the American forces reached the town, the local municipal government was quickly established under acting Mayor Francisco Barreto.