Rivendell founded (1697 S.A.)Rivendell founded (1697 S.A.) - Once the Rings had been forged and Sauron's motives revealed, war broke out in Middle Earth, the first recorded in Eriador (Beleriand is in Northern Middle Earth where the wars of the First Age were fought; Eriador is to the south).  Eregion was besieged (see below) and Gil-galad sent his lieutenant, Elrond, to assist his fellow Elves.  It was at this time, out of necessity, that one of the most treasured settlements of Middle Earth was built.


"...he (Sauron) turned upon the forces of Elrond.  Elrond had gathered such few of the Elves of Eregion as had escaped, but he had no force to withstand the onset.  He would indeed have been overwhelmed had not Sauron's host been attacked in the rear; for Durin sent out a force of Dwarves from Khazad-dȗm, and with them came Elves of Lórinand led by Amroth.  Elrond was able to extricate himself, but he was forced away northwards, and it was in that time [in the year 1697, according to the Tale of Years] that he established a refuge and stronghold at Imladris (Rivendell)." ~Unfinished Tales (The History of Galadriel and Celeborn)


Rivendell is its name in the Common Tongue, Imladris is the Sindarin name.