First Age
In some texts Tolkien referred to the 'First Age of Middle-earth' or the 'First Age of the World' rather than the 'First Age of the Children of Ilúvatar'. These variations had earlier starting points, extending the First Age back to the creation of Arda, but consistently ended with Morgoth's defeat in Beleriand. Each Age ended following a major event in the history of the Children of Ilúvatar.