['they', 'consider', 'myth', 'nature', 'due']
['<PRP>', 'consider-29.9-1-1-1', "Synset('fiction.n.01')", "Synset('physical_entity.n.01')", 'due']
Prior to their discovery fifty years ago in Andoria's northern hemisphere, they were considered to be simply a myth, due to their highly secretive nature.
prior to <PRP> Synset('speech_act.n.01') <DATE>3 in Andoria's Synset('northern.a.01') hemisphere, <PRP> were considered to be simply a myth, Synset('due.a.03') to <PRP> highly secretive Synset('physical_entity.n.01').