Alonis Cobaryn is one of the first captains to serve in the Federation Starfleet. Amongst the earliest captains, there was a divide between those considered "Butterfly Catchers", (Scientists) and Romulan War veterans, over what the future of the new Starfleet would be.
Cobaryn was on the butterfly catcher's side. He was a Rigellian, and was made captain-- first of an old Christopher ship, and later of the Daedalus-class USS Horizon. (Star Trek novel: Starfleet: Year One)
He is presumed to have still been in command when the ship made contact with the inhabitants of Sigma Iota II; he left behind a book, which had been a gift to him - "Chicago Mobs of the Twenties". This action contaminated the culture of the Sigma Iotians, who modelled their society after the Chicago Mobs. (TOS episode: "A Piece of the Action")