"Lady of the Lake" is the name of many fiddle tunes in various keys and styles. The Traditional Tune Archive (tunesearch.org) has nine versions cataloged, none of which are this one. This version comes from John Ashby & The Free State Ramblers.
John C. Ashby (1915-1979) began playing fiddle in 1926 at his home near Warrenton, Virginia. Sometime around 1940 John formed the Free State Ramblers, a band consisting of family and musician friends. “Free State” refers to a 12 square mile area near Warrenton that declared itself “free” in 1806, refusing to pay rent or taxes to landowner Chief Justice John Marshall.
I got the tune from John Lamancusa's collection (www.mne.psu.edu/lamancusa/tunes.html). The banjo tablature, based on the same source, is by John Letscher.