But historian Dr Anna Keay told the BBC that since its creation, the diamond had had many different owners, being in Persian and Afghan as well as Indian hands.
BBC: Koh-i-Noor diamond 'staying put' in UK says Cameron
2.
"We need to stress there is no evidence yet of ramps which may have been needed to launch newly constructed ships into the waters of the hexagonal basin, " Prof Keay said.
BBC: Roman shipyard found by British archaeologists
3.
"This was a vast structure which could easily have housed wood, canvas and other supplies and certainly would have been large enough to build or shelter ships in, " Prof Keay said.
BBC: Roman shipyard found by British archaeologists