In 1563, a surprise raid by undercover Ternatean forces aided by Portuguese upon Bo-ol resulted in destruction of much of the settlement, from mass looting to enslavement.

Consequently, a majority of the local Bol-anon survivors dispersed in an exodus to nearby islands, notably eastern Negros, Siquijor, and the northern coast of the Zamboanga peninsula where they founded Dapitan.

[5] Two years later in 1565, Esteban Rodríguez of the Legazpi expedition, caught by storm on his way back to Cebu from Bohol, sought refuge in the eastern shore of the island and met local Negritos called ata, agta, or ati.

His report upon returning to Cebu prompted Fray Andrés de Urdaneta to visit the island, landing in what is now Escalante in Negros Occidental.

In the same year, Capitán Mateo de Cádiz led a small expedition which reached an area near present-day Tanjay.

Capitán Miguel de Loarca followed with a larger expedition and force and proceeded to lay claim to what the Spaniards called the Island of Negros.

[6] From these few parishes along the coast, the priests administered the sacraments to the people in the hinterlands and served as mission to the wandering locals, converting them to Christianity.

The Definitorium dated June 11, 1580 mentions of the foundation of the Parish of Tanjay, with the communities of Dumaguete, Siaton, Marabago and Manalongon.

Later in 1851, at the request of the Bishop of Cebu, the Augustinian Recollect Fathers took over the spiritual care of the Parish and up to the time the diocesan clergy again took over.

It is a religious devotional festive dance with a mock battle depicting the war between the Moros and the Christians in Granada, Spain in centuries past.

It is based on the legend that St. James miraculously aided the Christians by riding on white horse from the heavens and slew hundreds of Moors.

Thus, the Sinulog is a religious exercise glorifying the Christians and honoring the feast day of Señor Santiago who is the patron saint of Tanjay and also of Spain.

The Sinulog was first performed in this town in 1814, under the auspices of the Catholic Church with Fray Fernando Félix de Zúñiga (1814–1816) as Parish Priest.

The war ended in 1945 but the Sinulog came to be resumed only in 1947 and continued to be an annual fiesta spectacle until 1970 when most of the long-time devotee participants were already too old to perform, or had already died.

Although the children's Sinulog bore the spirit of the Tanjay fiesta celebration, it was evident that they lacked the right expressive moments and authenticity of the former groups which were composed by matured men.

Tanjay's land area is 27,605 hectares (68,210 acres) and is utilized for agricultural, residential, commercial, industrial, educational, forestral and other purposes.

It is the only city in Negros Oriental with a very wide flat lowland, although mountainous and rolling hills are found in the hinterland barangays of Santo Niño and Pal-ew.