Complex sentence: Until his term ended in March 1812, Mendoza began the war for independence against the parts of Venezuela that still supported the Spanish monarchy, authored the Venezuelan Declaration of Independence, and also took part in constructing the first Constitution of the Republic of Venezuela.
Split into simpler sentences: Until his term ended in March 1812, Mendoza began the war for independence against the parts of Venezuela that still supported the Spanish monarchy, and also authored the Venezuelan Declaration of Independence. He also took part in constructing the first Constitution of the Republic of Venezuela.