The Lord of the Rings Ages Explained
In the Tolkien legendarium, an Age is a long period of time as divided by the Wise and lore masters of Arda - that is, Tolkien’s world as a whole. Four Ages are mentioned throughout Tolkien’s works, and the end of one and the start of another is often determined by a major historical event such as the defeat of a dark lord:
The First Age - which is very briefly depicted early on in The Rings of Power tv series - refers to the early years of the Elves, Dwarves and Men. Three stories by Tolkien that are set in the First Age are The Children of Hurin, Beren and Luthien, and The Fall of Gondolin. This age ended with the capture of Morgoth by the Valar. The Second Age - which we see on screen for the first time in the new tv show - was initially a prosperous one but it’s also marked by the ascent of Sauron. It is during this time that The Rings of Power were created. Stories of this time include the Drowning of Numenor, among others. The Second Age ended with The War of the Last Alliance and the defeat of Sauron. The Third Age - during which the events of The Lord of the Rings unfold, is marked by the gradual diminishing of Elves, and, of course, the War of the One Ring. It ends shortly after the permanent defeat of Sauron, with the departure of the Elves from Middle Earth. The Fourth Age for which we don’t have as much information started as prosperous for Hobbits, Dwarves, and Men, but by its end Men were the only dominant species in Middle Earth.
There are no records as such about later ages though a 1958 footnote in a letter by Tolkien suggested that Ages are now passing faster so that he lived in the Sixth or the Seventh.