Coriander, a member of the carrot family, is also sometimes referred to as Chinese Parsley or Cilantro. Coriander is actually the fruit [seeds] of the Coriander plant. Cilantro is the leaf of the coriander plant.
Coriander is probably one of the first spices used by human civilization, having been known as early as 5000 BC. The Romans spread coriander throughout Europe where it was widely used until the Renaissance, when exotic spices were introduced from the east. Coriander was one of the first spices to arrive with European settlers in America.