Santo Domingo was a former barrio of Ibalon, then the Municipality of Albay, now Legazpi City. It became a separate Municipality in 1749 through the uproar of its inhabitants and under the leadership of Diego Castellanos who took the matter first to the authorities in Manila, and to the Bishop of Ambos Camarines. The town of Santo Domingo was originally named Libog. Albay historians say that there were a number of stories on the origin of the name Libog. One version is that libog was derived from the Bikol word labog meaning "unclear water" for there was a time when no potable water was available in the locality. Another has it that the town might have been called after labog (jellyfish), which abound in its coastal water. Libod (behind) is another version because the town's position is behind the straight road from Legazpi to Tabaco across Basud to Santa Misericordia. Still another version is the corrupted form of the word libot which means "round about" or "winding way". In the early days of Spanish invasion, there were two routes passing through this place to Tabaco: one trail was straight or a short cut and the other was a round about (libot) way passing through the center of the town (via Poblacion). Later when the time came to classify and arrange this settlement to give it a political status as a visita of Binanuahan, now Legazpi Port, the corruption crept in – Libog for Libot. Hence, this town was named El Pueblo de Liboug, by the Spanish conquerors.