The Men of Dale were descendants of the Northmen who populated Rhovanion throughout the many ages. Their capital was Dale and later remnants fled Laketown. The Men of Dale were allied with the Dwarves in TA 2456 when Orcs from Mordor attacked.
In TA 2770, Smaug descended upon both Lonely Mountain and Dale probably from somewhere in Grey Mountains. He attacked and burned much of their town. Over two-hundred years after the destruction of Dale in TA 2941, one particular man named Bard the Bowman shot Smaug through a gap in his scaly armor with his Black Arrow with information from a Thrush that had contact with Thorin and Company. Thereafter, the Men of Dale's symbol was a Black Arrow so honoring the famous bowman. In TA 3019 during the War of the Ring, they aided the Dwarves in defending the Lonely Mountain from the Easterling Empire.
The Men of Dale are also called Bardings no doubt because Bard I (the Bowman) defeated Smaug and founded a new kingdom.
Portrayal in adaptationsEdit
Peter Jackson's The Hobbit film trilogyEdit
In Peter Jackson's "The Hobbit" film trilogy, the Men of Dale (as well as Lake-town) are directly derived from medieval Russian influences (i.e., Kievan Rus' and its successor states). For instance, the warriors of Dale (adorned with conical, medieval Russian-style furred helmets and heavily-furred garbs) appear like the knights and warriors of the Rus' states of old.
Of course, due to the intricate nature of medieval Russian ethno-history, one also detects Nordic, Baltic, Finnic, and Turkic influences as well. Essentially, the films clearly utilize medieval Russian influences to depict the Men of Dale (and Lake-town) as a part of the East - as Professor Tolkien would have intended.