[3] Robert M. Mayo enlisted in the Confederate States Army as a major on May 18, 1861, and helped organize the 47th Virginia Infantry the next month with Col. George William Richardson.

The unit was initially based at Stafford and assigned to protect the shores of the Potomac and Rappahannock Rivers near most members' homes, but was told to withdraw in March 1862 before an expected advance of Union troops under General George McClellan.

Mayo was elected the unit's colonel on May 1, 1862, and was wounded in the arm at Seven Pines opposing the Union Peninsular campaign.

[4] His elder brother Joseph Campbell Mayo, who graduated in VMI's class of 1852, held similar positions with the 3rd Virginia Infantry (based in Norfolk and one of the companies originally assigned to capture the abolitionist John Brown in 1858 and early in the war defended the Atlantic Coast).

J.C. Mayo was wounded at Sharpsburg and Gettysburg, and after the war practiced law in Richmond and became the treasurer of Virginia in 1872, before returning home to Westmoreland County and becoming its Commonwealth's Attorney, and eventually dying at his mansion "Auburn" in 1898.

[6] In 1881 voters in Northumberland and Westmoreland Counties elected Mayo to the Virginia House of Delegates (a part-time position), where he succeeded S. B.

Incumbent Democrat George T. Garrison of Accomack County according to the initial tally won 70 more votes than challenger Mayo.