Upon the arrival of the Spaniards in the Philippines some of them travelled along the seacoasts looking for a better place to live in.
Travelling without any fixed direction, they happen to pass by this place that is partly hidden between two sharp points extending to the sea. The Spaniards asked the Aeta, who was travelling with them as their guide, for the name of that place.
The Aeta answered that that is called "lumbak" meaning lying between two hills. As their ship was crossing this place they sighted a flock of herons flying above them.
When the Spaniards inquired about them to their guide, the Aeta replied, "Iyon po ay mga ibong tagak." And so from "lumbak" and "tagak" came "bak" and "gak", and soon it became Bagac.