An interesting possibility regarding Gene Roddenberry's inspiration for the character of Zefram Cochrane...
Lord Thomas Cochrane, 10th Earl of Dundonald, was a Scottish man of near-to-mythic reputation; a British naval captain during the Napoleonic era who also served on behalf of Peru, Brazil, and Chile in their liberation from Spain and Portugal. His exploits are detailed in numerous literary works, immortalized in fictional characters - specifically C.S. Forrester's Horatio Hornblower and Patrick O'Brian's Captain Jack Aubry.
In David Cordingly's book, Cochrane: The Real Master and Commander, he writes:
"Cochrane was the very epitome of the Romantic hero. His life has an epic quality and was marked by a dramatic succession of ups and downs. Remarkable triumphs were all too often followed by disappointment and recriminations. Like so many heroes he was a flawed character with a temperament which led him into conflict and disputes. He imagined enemies where there were none and made enemies of people who should have been his friends. He was frequently out of step with his times and lacked the insight and the humility to understand why this should be and to adapt to it. His most damaging fault was his pursuit of money and his relentless determination to make his fortune."
(Source: Cordingly, David, Cochrane: The Real Master and Commander, as cited in "Talk of the Nation," 18 Sept 2007, NPR.)
Link: http://www.npr.org/templates/story/story.php?storyId=14505058
It would certainly appear that Lord Thomas Cochrane fits the bill of Roddenberry's volatile Zefram, who is destined to make history in spite of himself.
A commonly known piece of trivia also supports this speculation. Consider Gene Roddenberry's own description of Captain James T. Kirk in the third revision of the Star Trek storyline from April 1967:
Played by William Shatner, Kirk is about thirty-four, an Academy graduate, rank of Starship Captain. A shorthand sketch of him might be "A space-age Captain Horatio Hornblower", constantly on trial with himself, a strong, complex personality...On the other hand, don't play Kirk like the captain of an 1812 frigate in which nothing or no one moves without his command."
(Source: https://www.bu.edu/clarion/guides/Star_Trek_Writers_Guide.pdf)
Did I mention that Lord Cochrane was a frigate captain?
LLAP, Clan Cochrane in North America
Visit us online at ClanCochrane dot org!