Complex sentence: Increased demand from prospective students led to the building of a modern high school, adjacent to the Academy, which opened in 1952 and was Named "Maria" for their foundress Mother Maria and the Blessed Mother.
Split into simpler sentences: Increased demand from prospective students led to the building of a modern high school, adjacent to the Academy, in 1952. It was named Maria High School both for their foundress Mother Maria and the Blessed Mother.