There are periods of time when people lose knowledge, Rees said, citing the Dark Ages as an example in Western history.
Standard nonsense history from Rees concerning the history of the west.
However, its probably true the Chinese did come across the ocean, just as it is also likely that others like the Phoenicians did (how hard could it be if the Vikings made it in their primitive crafts?). There are too many good old maps pre-1500 showing the Americas, Antarctica, and Australia, as Charles Hapgood pointed out.