History of Arda
In J . R . R . Tolkien's legendarium , the history of Arda , also called the history of Middle-earth , began when the Ainur entered Arda , following the creation events in the Ainulindalë and long ages of labour throughout Eä , the fictional universe . 
<triplet> legendarium <subj> J. R. R. Tolkien <obj> creator <subj> Ainulindalë <obj> fictional universe described in <subj> fictional universe <obj> instance of <triplet> Ainur <subj> legendarium <obj> from narrative universe <triplet> Arda <subj> legendarium <obj> from narrative universe <triplet> Ainulindalë <subj> J. R. R. Tolkien <obj> author <subj> legendarium <obj> takes place in fictional universe <triplet> Eä <subj> legendarium <obj> from narrative universe