Exiles of Gondolin
The Exiles of Gondolin were survivors of the Fall of Gondolin.
During the confusion of the sack of the city, Tuor and Idril gathered all the remnants of the Gondolindrim they could find. They escaped through Idril's secret way, a tunnel that led to Tumladen. Thanks to the burning of the fountains and the city of Gondolin, they were covered in fume and mists, so they could cross the plain unnoticed.
The group ran to Cirith Thoronath, where Glorfindel killed the Balrog, saving them. Then they passed over the mountains, reaching the Sirion river, which they followed south. After many dangers, they came to Nan-tathren, and they could rest there for a while, healing their wounds, but not their sorrow.
Other versions of the legendarium
In the Lost Tale of "The Fall of Gondolin", the escape and wanderings of the Exiles is told with more detail than any other version. Those who escaped the city and reached the Eagles' Cleft were counted as a nigh eight hundreds. But in their wanderings suffered attacks and diseases, so when they reach the Land of Willows years later they were less: including children, three hundred and twenty men, and two hundred sixty women. When they moved to the mouths of Sirion, they took the name of Lothlim ("People of the Flower"), as the name Gondothlim saddened their hearts.