Complex sentence: It was founded in 1977 by Gergina Toncheva, who was the first principal of the school and gave its name "St. Constantine-Cyril" The Philosopher "".
Split into simpler sentences: It was founded in 1977 by Gergina Toncheva, who was the first principal of the school. The School was named after "St. Constantine-Cyril" The Philosopher "".