The Krivani were a species that was ultimately annihilated.
The Krivani had been isolated for millenia before venturing beyond their solar system. They became involved in a dispute with a neighbouring system and were wiped out in the ensuing war.
They had developed an advanced interstellar drive system for their ships. One Krivani ship, passing through Earth's system, exploded, and its propulsion unit, programmed to home in on the nearest planet, landed on Earth. The Doctor first detected its signal during the Trojan War but was unable to take care of it. Later, the Seventh Doctor and Ace tracked it down in 20th century Constantinople. (PROSE: Ante Bellum)