Complex sentence: The War of the Reform was a Mexican civil war fought from December 1857 to January 1861, launched by the liberals and the moderate revolutionists dissatisfied with the Catholic Church's stronghold on government affairs.
Split into simpler sentences: The War of the Reform was a Mexican civil war fought from December 1857 to January 1861. It was launched by the Liberals and the Moderate Revolutionists, who were dissatisfied with the Catholic Church's stronghold on government affairs.