Complex sentence: Besant became President of the Theosophical Society in 1907, and added considerable weight to the belief of Maitreya's imminent manifestation, which became a commonly held expectation among Theosophists.
Split into simpler sentences: Besant became President of the Theosophical Society in 1907, and added considerable weight to the belief of Maitreya's imminent manifestation. This idea was widely discussed, and became a commonly held expectation among Theosophists.