Kim Il-sung had his brother and heir apparent at that time, Kim Yong-ju, pen the Ten Principles for the Establishment of a Monolithic Ideological System. This new set of policies made Kim Il-sung's rule unchallengeable and expanded his cult of personality to cover other members of the Kim family. His son, Kim Jong-il, took part in the purges and took over the party's Propaganda and Agitation Department (PAD) in what was the first political task delegated to him by his father, paving the way to his increasingly influential role in the politics of the country.