Due to progress in economy and political life of the people living in this place, a young man by the nameof teodoro Mendoza initiated a move to make the place a distinct and independent barrio. He contacted the leaders of the sitios of Guitasin, balanoy, and Balite (now Proper) all of Barrio Nag-iba and the leaders of thr sitios of Aguada, Nangkaan, Panay, all of the Barrio Bagalangit on his plan to have their sitios created to a barrio. This young man conferred with Mr. Silverio D. Sandoval, former Municipal Secretary of Mabini on how to petition the Municipal Council and the Provincial Board on the manner of creating this Sitios into a Barrio. Because of mr. Sandoval's desire to help the people and of his knowing that the places or sitios deserve to be an independent Barrio drafted the petition which was signed by the residents of six (6) Sitios and presented to the Municipal Council for action. The Municipal Council by virtue of its Resolution No. 28, series of 1964, and pursuant to the provisions of Republic Act No. 3590 otherwise known as the Barrio Charter, acted immediately by approving the petition of the residents of the Sitios of Aguada, Nangkaan and Panay of Barrio Bagalangit and the Sitios of Guitisan, Balite, and Balanoy of Barrio Nag-iba, and forwarded it to the Provincial Board of Batangas for final action. Also on that year, the Provincial Board of Batangas acted favorably on the said petition declaring the creation of a new Barrio to be called San Teodoro. The name San Teodoro was given by Mr. Sandoval for he could not think of any other name when he drafted the petition except that he would like to have the barrios of Mabini named after Patron Saints.

This Barrio is a mountainous place although it is along the shores of the Balayan Bay noted for its richness in natural resources like mines, gazring land, agricultural products and fish. The settlers had their own houses built of light materials like "cogon", bamboo, and nipa usually located on places between ravines. There were naturally industrious. They doubled their efforts in securing a decent life for their loved ones. They were also thrifty in all ways. They used spark stones in building fire in cooking, as there were no matches during that time. All night, they use sap (sahing) of the "palsahingin" tree by putting it into the bamboo tubes to be used as their lamps. They marketed their agricultural and sea products in the town of Taal, formerly called Bonbon by "bancas" spending the whole day for travel. In return they bought sugar, coffee, salt, and other house needs. Travelling to neighboring places was done by traversing mountain slopes and ravines with pathways just enough for one to pass on.

How the early settlers were clothed was incomparable to the present residents. Their clothing were made of abaca fibers woven by women. Like in the neighboring barrios, men wore dyed trousers and collar-less shirt. Their footwear was called "panyapak" which was made of dried skin of cows twisted with abaca fibers.