On March 8, 1421, the largest fleet the world had ever seen set sail
from China to "proceed all the way to the ends of the earth to collect
tribute from the barbarians beyond the seas." When the fleet returned
home in October 1423, the emperor had fallen, leaving China in political
and economic chaos. The great ships were left to rot at their moorings
and the records of their journeys were destroyed. Lost in the long,
self-imposed isolation that followed was the knowledge that Chinese
ships had reached America seventy years before Columbus and had
circumnavigated the globe a century before Magellan. And they colonized
America before the Europeans, transplanting the principal economic crops
that have since fed and clothed the world.