Much of the following chronology is taken from Tolkien's "Tale of Years." Birth and death dates of the chieftains are from "Peoples of Middle-Earth." I repeat that material here to help orient the reader regarding the characters, their ages, and their experience of the past. Ages for most of the characters, including of course all "original" characters, are my own invention, but are compatible with canon. Please note there are no plot spoilers in this chronology.
2740. Orcs renew their invasions of Eriador. Arassuil is chieftain of the Dúnedain at this time.
2747. An Orc-band invades the Northfarthing.
2757. Birth of Argonui son of Arathorn I.
2758. Rohan attacked from west and east and overrun. Gondor attacked by fleets of the Corsairs.
2758-9. The Long Winter follows. Great suffering and loss of life in Eriador and Rohan. Gandalf comes to the aid of the Shire-folk.
2759. Saruman takes up his abode in Isengard.
2770. Smaug the Dragon descends on Erebor. Dale destroyed. Thror escapes with Thrain II and Thorin II.
2775. Birth of Saelind, wife of Argonui.
2784. Death of Arassuil son of Arahad II. Arathorn I becomes chieftain.
2790. Thror slain by an Orc in Moria. The Dwarves gather for a war of vengeance.
2793. The War of the Dwarves and Orcs begins.
2799. Battle of Nanduhirion before the East-gate of Moria. Dain Ironfoot returns to the Iron Hills. Thrain II and his son Thorin wander westwards. They settle in the South of Ered Luin beyond the Shire (2802).
2800-64. Orcs from the North trouble Rohan.
2803. Birth of Goenor.
2820. Birth of Arador son of Argonui.
2825. Birth of Ingold.
2841. Thrain II sets out to revisit Erebor, but is pursued by the servants of Sauron.
2845. Thrain the Dwarf is imprisoned in Dol Guldur; the last of the Seven Rings is taken from him.
2848. Death of Arathorn I son of Arassuil. Argonui becomes chieftain.
2849. Birth of Hallor.
2850. Gandalf again enters Dol Guldur, and discovers that its master is indeed Sauron, who is gathering all the Rings and seeking for news of the One, and of Isildur's Heir. He finds Thrain and receives the key of Erebor. Thrain dies in Dol Guldur.
2851. The White Council meets. Gandalf urges an attack on Dol Guldur. Saruman overrules him. Saruman begins to search near the Gladden Fields.
2862. Birth of Dírhael.
2870. Birth of Hawk (Herion).
2872. The White Tree of Gondor dies, and no seedling can be found. The Dead Tree is left standing.
2873. Birth of Arathorn II son of Arador. Birth of Beleg husband of Ariel.
2879. Birth of Ivorwen daughter of Gilbarad.
2885. Stirred up by emissaries of Sauron the Haradrim cross the Poros and attack Gondor.
2901 Most of the remaining inhabitants of Ithilien desert it owing to the attacks of Uruks of Mordor.
2902. Birth of Daeron.
2907. Birth of Gilraen mother of Aragorn II.
2911. The Fell Winter. The Baranduin and other rivers are frozen. White Wolves invade Eriador from the North.
2912. Great floods devastate Enedwaith and Minhiriath. Tharbad is ruined and deserted. Death of Argonui. Arador becomes chieftain.
2916. Birth of Iorlas son of Dírhael.
2920. Birth of Ríannon, Iorlas's wife.
2927. Cobin Graywacke born in Bree.
2928. Birth of Halbarad.
2929. Arathorn son of Arador of the Dunedain weds Gilraen. Birth of Damrod.
2930. Arador slain by Trolls. Arathorn II becomes chieftain. Malbeth, Hawk's grandson, born.
2931. Aragorn son of Arathorn II born on March 1.
2933. Arathorn II slain. Aragorn becomes chieftain. Gilraen takes Aragorn to Imladris. Elrond receives him as foster-son and gives him the name Estel (Hope); his ancestry is concealed.
2936. Birth of Fíriel.
2938. Birth of Rodnion and Rodnor, Hawk's grandsons.
2939. Saruman discovers that Sauron's servants are searching the Anduin near Gladden Fields, and that Sauron therefore has learned of Isildur's end. He is alarmed, but says nothing to the Council.
2940. Ariel daughter of Arador dies in childbed.
2941. Thorin Oakenshield and Gandalf visit Bilbo in the Shire. Bilbo finds the Ring. The White Council meets; Saruman agrees to an attack on Dol Guldur, since he now wishes to prevent Sauron from searching the River. Sauron having made his plans abandons Dol Guldur. The Battle of the Five Armies in Dale. Death of Thorin II. Bard of Esgaroth slays Smaug. Dain of the Iron Hills becomes King under the Mountain (Dain II).
2942. Bilbo returns to the Shire with the Ring. Sauron returns in secret to Mordor.
2943. Marriage of Iorlas and Ríannon.
2944. Bard rebuilds Dale and becomes King. Gollum leaves the Mountains and begins his search for the "thief" of the Ring.
2946. Birth of Lalaith daughter of Iorlas.
2949. Gandalf and Balin visit Bilbo in the Shire.
2951. Sauron declares himself openly and gathers power in Mordor. He begins the rebuilding of Barad-dur. Sauron sends three of the Nazgûl to reoccupy Dol Guldur.
Elrond reveals to Estel his true name and ancestry, and delivers to him the shards of Narsil. Arwen, newly returned from Lorien, meets Aragorn in the woods of Imladris.
October 1. Aragorn leaves Rivendell for the Angle.