Complex sentence: In 1926 the OSE which in affiliation with the Theosophical Society was by then producing a number of publications and propaganda material, organized its own publishing arm, the "Star Publishing Trust" based at Eerde, Ommen, the Netherlands.
Split into simpler sentences: In 1926 the OSE, which in affiliation with the Theosophical Society was by then producing a number of publications and propaganda material, organized its own publishing arm. Named "Star Publishing Trust", it was based at Eerde, Ommen, the Netherlands.