Armesto was the final captain of the Flotilla vessel Brazilia. He, along with Captains Omdurman of the Baghdad and Zamudio of the Palestine, were deceived by Captain Haussmann of the Santiago, who had initiated a scheme to arrive at Journey's End first.
After arguing against any attempt to stop their engine's antimatter flow in order to sync-up their deceleration curves with the Santiago's, Captain Zamudio ignored Armesto's council and accidentally destroyed the Palestine. After that event Armesto allied his ship with the Baghdad, and united their colonization efforts.
Centuries after the fact, the descendants of the crews and passengers of the Brazilia and the Baghdad would think of themselves as a single nation.