The concept of a spherical Earth dates back to ancient Greek philosophy from around the 6th century BC,[1] but remained a matter of philosophical speculation until the 3rd century BC when Hellenistic astronomy established the spherical shape of the earth as a physical given.
http://en.wikipedia.org/wiki/Spherical_Earth
The myth of the Flat Earth is the modern misconception that the prevailing cosmological view during the Middle Ages saw the Earth as flat, instead of spherical.
http://en.wikipedia.org/wiki/Myth_of_the_Flat_Earth
you can choose to attack me or you can choose to attack my argument.