rutherford wrote many books as well. he made some changes to russell's teachings and required all the study groups, or congregations, around the world to agree to the teachings and rules set by the watch tower society in new york. he told all members to no longer celebrate all holidays, singing at religious meetings was strictly prohibited and preaching from door to door about god's kingdom and to distribute watch tower society publications so more people would hear the message was mandatory. many members did not agree with rutherford's harsh changes, and some started their own groups. in 1931 rutherford called his group "jehovah's witnesses" to tell it apart from the other groups. by the time rutherford died in 1942, the religion had a worldwide membership of 115,000.