Last Alliance of Elves and MenLast Alliance of Elves and Men - Only the combined strength of the free peoples of Middle Earth could defeat Sauron.

 

"Now Elendil and Gil-galad took counsel together, for they perceived that Sauron would grow too strong and would overcome all his enemies one by one, if they did not unite against him.  Therefore they made that League which is called the Last Alliance, and they marched east into Middle-earth gathering a great host of Elves and Men; and they halted for a while at Imladris (Rivendell).  It is said that the host that was there assembled was fairer and more splendid in arms than any that has since been seen in Middle-earth, and none greater has been mustered since the host of the Valar went against Thangorodrim.  From Imladris they crossed the Misty Mountains by many passes and marched down the River Anduin, and so came at last upon the host of Sauron on Dagorlad, the Battle Plain..." ~The Silmarillion (Of the Rings of Power and the Third Age)