the Third Age

The Third Age is the current age of the world. It began when the Second Unmaking ended.  This sounds simple, but historians cannot agree on when the Second Unmaking ended.
Historians do not agree on whether the Second Unmaking ended when the last Demon Lord was destroyed (which historians do not agree which year this occurred withing a 10-50 year window) or when the last of the Demon armies were dispersed (which historians argue took anywhere from 20 years after the last Demon Lord died to 400 years after the last Demon Lord died).
Some historians believe the Third Age officially began when the first humans were created which again there is no consensus when this happened.
Most historians estimate the Third Age could be anywhere between 3000 and 5000 years old.