Arya Samaj in Tanzania had been in existence since the early 1900s and prior to independence the whole of East Africa was served by a single Arya Samaj. After independence a separate Pratinidhi Sabha was formed in Tanzania on 19 July 1974.
Read more about Arya Samaj In Tanzania: History, Arya Samaj in Tanga, Arya Samaj in Zanzibar