Greeting from Bulger, Pennsylvania (near Pittsburgh)

I've traced my husband's ancestry back to Govan, Lanarkshire, Scotland in 1660, where the oldest name on the "familysearch" site is simply Darnlie, b. 1660. Darnlie and Mrs. Darnlie are listed as parents of John Darnlie b 1684, then the line/gerernations progress as follows: James Darnlie b 1712, James Darnlie b 1745, James Darnlie b 1776, James Patterson Darnley b 1803, James Patterson Darnley Sr b 1830, James Patterson Darnley Jr b 1856 -- moved to Lonaconing, MD USA, Gilbert Darnley b 1897, Robert Cochran Darnley 1927, Robert Eugene Darnley b 1947 (my husband), Robert Eugene Darnley Jr b 1969, and Matthew Robert Darnley b 1998.

Darnlie spelling isn't used after 1800, but Darnley goes back to before the infamous Henry Darnley marred Mary, Queen of Scots.

History shows that King James II of England had many illegitimate children, one of whom was named James Darnley, born to Catherine Sedley in 1684 and died 1685. Could there have been more royal descendents, born to humble country folk and not given titles and land? Could the ordinary American Darnleys also be descended from a royal line? Or did they just live and work on the Darnley lands and took the name?

I'm just curious, and would love to know. Has anyone followed the commoner Darnley trail back to Royal origins?