58th century

The 58th century was visited once by the Doctor, in an alternate timeline, where he visited Helios 3 in 5738. (PROSE: Spiral Scratch)

Earlier, in 5720, following World War VI, archaeologists on Earth discovered the ancient remains of a Khorlthochloi spaceship, though they never learned anything about its creators or why it had crashed. (PROSE: Synthespians™)