A 100% fanon timeline of the series, based on fanon writing I do (I'll get the links up in the main profile). Dates will be added as they're revealed, as it's far more expansive than what's on display here. And yes, the 'Age' System is taken from the LotR books. Sue me.
As for writing in fics, I use a shorthand writing system (eg. the year 3000 of the Fourth Age would be 4A-3000
-Unknown Date: The djinn aid humanity in battle.
-Late First Age: The Wise One and Sol enter a pact of some sort.
-It's at the end of this age that Sol takes physical form for the last time.
-Unknown Date: The djinn aid humanity in battle. Again.
-2551: Last year of the Second Age.
Third Age (aka LostAge/Golden Age of Man
-Last year: Alchemy is sealed.
-1: Vani and Abel have a discussion in Sol Sanctum concerning "what really happened" when Alchemy was sealed.
-400 (approx): Goma Cave falls into disrepair.
-2891: Lunpa finds a cave system that becomes his hideout.
-2896: The town of Lunpa is officially founded, many having flocked to Lunpa’s banner.
-2927: Heph is born.
-2938: Kraden, as a scholar in service of Tolbi, recovers some scrolls dated at around 3000 years. They're unable to be translated and are stored.
-2967: Root is born.
-2968: Jack (the Ripper) is born.
-2972: Heph becomes mayor of Vale.
-Tinker is born.
-2975: Dodonpa seizes power in Lunpa.
-2976: Suldan is born.
-2977: Pavel is born. Sara is born a few months later.
-2980: Kay is born.
-2982: Felix is born.
-Pavel begins training in the use of shortswords.
-2983: Garet is born. Isaac is born a few months later.
-2984: Jenna is born.
-2985: Ivan is born.
-2988: Something happens in Vale Cave. Kite witnesses it.
-2990: Isaac, Garet, Jenna, Felix and Kay play a game at Christmas, involving Isaac and Felix 'rescuing' Jenna and Kay from Garet. Suffice to say, things don't go as smoothly as anticipated.
-2992: Aaron is born.
-2997: Attempting to recover the Elemental Stars, Saturos and Menardi trigger a storm over Vale.
-One month after the storm occurs Kraden visits Isaac and Jenna, offering to teach them the ways of psyenergy and alchemy. They accept, along with Garet volunteering.
-2999: Someone enters Sol Sanctum, the manner of doing so unexpected.
-3000: The Broken Seal begins.