Ropes was born on April 28, 1836, in Saint Petersburg, the son of a leading merchant of Boston who was engaged in business in Russia. At the age of fourteen, his family having returned to Massachusetts, he developed an infection of the spine which eventually became a permanent deformity. John Codman Ropes memorial plaque at Trinity Church in Boston He entered Harvard in 1853 and graduated in 1857. His interests as a young man were chiefly religious, legal and historical, and these remained with him throughout life, his career as a lawyer being conspicuous and successful. But it was the outbreak of the American Civil War in 1861 which fixed his attention principally on military history. He ceaselessly assisted with business and personal help and friendship the officers and men of the 20th Massachusetts regiment, in which his brother, Henry Ropes, was killed in action at Gettysburg, and after the war he devoted himself to the collection and elucidation of all obtainable evidence as to its incidents and events. In 1865, he co-founded the Boston-based law firm Ropes & Gray with John Chipman Gray.