sentences:  Under their fourth leader, Baba Gurdit Singh, some of the Nirankari took an interest in the Singh Sabha Sikh revivalist movement.The Nirankaris helped to bring the Anand Marriage Act of 1909 to the attention of the Sikh populace.The movement's fifth Guru, Sahib Hara Singh (1877–1971), started to reorganize the movement, and was later succeeded by his eldest son, Baba Gurbax Singh.