From 1916 to 1935, senators were elected by districts. The country was divided into twelve (12) senatorial districts. Cebu was then the 10th senatorial district. This was by virtue of the “The Philippine Autonomy Act,†otherwise known as the Jones Law, enacted on August 29, 1916 by the United States Congress. This made the Philippine Congress bicameral, which was then unicameral as provided by the Philippine Bill of 1902. Each senatorial district elected two senators.
The first senatorial election was held on October 3, 1916. The following served as senators representing the 10th district:
Celestino Rodriguez, Filemon Sotto (1916-1919)
Celestino Rodriguez, Filemon Sotto (1919-1922)
Sergio Osmeña Sr., Celestino Rodriguez (1922-1925)
Sergio Osmeña Sr., Pedro Rodriguez (1925-1928)
Sergio Osmeña Sr., Pedro Rodriguez (1928-1931)
Sergio Osmeña Sr., Manuel C. Briones (1931-1934)
Sergio Osmeña Sr., Manuel C. Briones (1934-1935).
The election of senators by districts was changed following its abolition by the 1935 Constitution and when it was amended in 1940, the Senate was restored but they were elected at large, meaning the entire electorate of the country votes for their senators. The first election of senators at large was held in November of 1941.