Complex sentence: The first 200 years of Joseon were marked by relative peace and saw the creation of the Korean alphabet by Sejong the Great in the 15th century and the increasing influence of Confucianism.
Split into simpler sentences: The first 200 years of Joseon were marked by relative peace. During this period, the Korean alphabet was created by Sejong the Great in the 15th century and there was increasing influence of Confucianism.