Kirk is known to be based on Horatio Hornblower. (from a recent answer on SFF.SE)
Is there some reference showing that ("based on") to be an actual fact as opposed to inference?
I'm not asking for comparison of characters (as is loosely covered on Memory Alpha's Hornblower page) which is merely circumstantial and doesn't prove "based on". Similarities between the two could be as easily explained by archetypes as by intentional homage.
What I'm seeking is information originating from Roddenberry, or someone else on Star Trek creative team, indicating that there was intent for Kirk's character to resemble Hornblower, or specific influence of those books on creative team.