The Constitutional Convention of 1970 was called to change the then Philippine Constitution, written to establish the Commonwealth of the Philippines. A special election was held on November 10, 1970 to elect the delegates.
Former Philippine President Carlos P. Garcia was sworn in as the President of the Constitutional Convention on June 11, 1971. However, he died three days after taking oath. Former PresidentDiosdado Macapagal replaced Garcia. Sotero H. Laurel served as the President Pro-Tempore of the convention.
Other prominent delegates were former Senators Raul Manglapus and Roseller T. Lim. Other delegates would become influential political figures including Hilario Davide, Jr., Marcelo Fernan, Sotero Laurel, Aquilino Pimentel, Jr., Teofisto Guingona, Jr., Raul Roco, Edgardo Angara, Richard Gordon, and Margarito Teves.
The work of the Convention was affected by the declaration of martial law in September 1972 by President Ferdinand Marcos. Eventually, on November 29, 1972, the Convention approved the new constitution. It was submitted to a vote in the 1973 constitutional plebiscite. The results of the plebiscite and the legality of the 1973 Constitution was questioned before the Philippine Supreme Court in the Ratification Cases. The constitution was upheld. Marcos would continue to rule as a dictator until being ousted by the People Power Revolution in 1986.
https://en.wikipedia.org/wiki/Philippine_Constitutional_Convention_election,_1970