Complex sentence: After CCP's split with the KMT in 1927, Wang and Mif attended the CCP's 5th National Congress in Wuhan, after which Wang became Secretariat for the CCP's Propaganda Department for two months.
Split into simpler sentences: After CCP's split with the KMT in 1927, Wang and Mif attended the CCP's 5th National Congress in Wuhan. After the congress, Wang became the Secretariat for the CCP's Propaganda Department for two months.