Complex sentence: It is believed that Chowdeshwari Devi came from Varanasi to Nandavaram and 500 Brahmin families who stayed back at Nandavaram became Nandavarika Brahmins, a section of who became the custodians of the Chowdeshwari Devi temple.
Split into simpler sentences: It is believed that Chowdeshwari Devi came from Varanasi to Nandavaram. The 500 Brahmin families who stayed back at Nandavaram became Nandavarika Brahmins, a section of who became the custodians of the Chowdeshwari Devi temple.