The Markonians were a humanoid species native to the Markonia sector in the Delta Quadrant. Following the destruction of their homeworld, the Markonians became a nomadic people fostering good relationships between species by trade and diplomacy. (VOY - Distant Shores short story: "Brief Candle", ST video game: Star Trek Online)
A long time before the 24th century, the Markonian homeworld was destroyed and the Markonians became a people of refugees. The Markonians adapted well to their new nomadic lifestyle and became traders, explorers and diplomats. Their status as neutral party earned the Markonians the trust of neighboring species, and the Markonians helped diffuse territorial conflicts.
On stardate 53049.2 (January 19, 2376), the Federation made first contact with the Markonians when USS Voyager docked at the Markonian outpost. Members of various species from the outpost visited Voyager, including at least one Markonian. (VOY episode: "Survival Instinct") Voyager's Lieutenant Commander Chakotay was impressed by the Markonians and believed the interstellar community they had set up was a Federation in the making.