It was exactly December 13, 1948 when four La Salette Missionaries from the Immaculate Heart of Mary Province in the U.S.A. arrived in the Philippines in response to the plea made by Bishop Jurgens of Tuguegarao. The diocese was then badly in need of religious communities to attend to the spiritual welfare of the growing populace. From Manila the La Salette Fathers decided to set their base in San Mateo, Isabela where the people warmly received them. For a while, they stayed in the house of the late Mr. and Mrs. Mateo Cadeliña in the Poblacion, now Old Centro.

After serious and prayerful reflections, the La Salette Fathers were convinced that putting up a school would hasten the spread of Mary’s vision. Thus in 1949, they founded a school for first and second year students. The school was named Fatima High School. Its first Director was Fr. Paul Doulliard and the Principal was Mr. Jose Hammond of Tumauini. After a year, the school was renamed La Salette High School to Identify it with La Salette Community.

Development came soon as the years went by. The municipal building and other public offices were built at the junction about a kilometer away from the school to give room for expansion. People started moving into the area, giving rise to what we now call Poblacion.

To fully cater to the education needs of the people, the La Salette Fathers also transferred the school to a piece of land donated by the late don Mateo Cadeliña, founder and ex-mayor of San Mateo. Third and fourth year classes were added for the school year 1950-1951. There were added twenty graduates at the end of the school year.