Full Idea
He was the first person who asserted that the earth was of a spherical form.
Gist of Idea
He was the first person to say the earth is spherical
Source
report of Parmenides (fragments/reports [c.474 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Pa.2
Book Reference
Diogenes Laertius: 'Diogenes Laertius', ed/tr. Yonge,C.D. [Henry G. Bohn 1853], p.384