Complex sentence: Zamboanga del Norte was part of the representation of Zamboanga Province until 1953 and Region IX from 1978 to 1984, and from 1984 to 1986, it elected 2 assemblymen at-large.
Split into simpler sentences: Zamboanga del Norte was part of the representation of Zamboanga Province until 1953 and Region IX from 1978 to 1984. From 1984 to 1986, it elected 2 assemblymen at-large.