The Last Alliance and its Army

[mhagain]

Originally Posted by Mithadan

Elendil, Anarion and Isildur arrived in Middle-Earth in SA 3319. The Last Alliance was formed a mere eleven years later, in 3430.

You've got your timespan wrong, it's one hundred and eleven years, not eleven. Still short by the standards of some parts of the chronologies, but ample to establish kingdoms and raise armies among a mixture of locals, settlers and exiles.