Complex sentence: The majority of contemporary Theosophists believed the material regarding Alcyone's "lives" to be genuine and important; however it also added to or initiated disputes within Theosophical circles, and has for various reasons been considered controversial inside and outside Theosophy.
Split into simpler sentences: The majority of contemporary Theosophists believed the material regarding Alcyone's "lives" to be genuine and important. It also added to or initiated disputes within Theosophical circles, and has for various reasons been considered controversial inside and outside Theosophy.