Robert Maxwell Martin and I are both descendants of William Roark, a Revolutionary War veteran (see Roark posts). According to "A History of Muhlenberg County (KY)" by Otto Rothert, published in 1913:
The Civil War produced no higher type of the fearless and danger-loving soldier – no more perfect exemplar of the romantic and picturesque partisan ranger – than Robert Maxwell Martin of Muhlenberg.
Robert Maxwell Martin was a Confederate in the midst of Union supporters. It was not uncommon, especially in border states (including Kentucky) for families to have divided loyalties in the Civil War. See a specific reference to Robert Maxwell Martin regarding "brother against brother" here.
Among Robert M. Martin's heroics on behalf of the Confederacy included:
Saving General John Hunt Morgan’s life in Tennessee [Click on "See Full Article" to see Robert Maxwell Martin's obituary in the NY Times referencing this incident] More detail can be seen here.
Participated in a plot to kidnap Vice-President elect Andrew Johnson in Louisville as he was enroute to Washington (which failed when Johnson changed his mode of travel)
Head of "The Confederate Army of Manhattan;" a group of eight who plotted to set fires in New York partially in retaliation for General Sherman's actions, and with the help of the Copperheads, take over Federal buildings in NY on Election Day (1864). A parallel between the Copperheads of the 1860's and modern day politics on linked blog.
Possibly knew John Wilkes Booth....
"It is said that Robert M. Martin was tried and convicted of treason..." at any rate, he was held at Fort Lafayette in New York and interrogated in an attempt to gain incriminating information about Jefferson Davis.
After the war, Robert Maxwell Martin married Caroline Wardlaw; that was probably the worst decision of his life. After living in Evansville, Indiana, and Louisville, Kentucky, after the Civil War, Robert died in New York City.