Who said "To think truly is to think of what is, and nothing else."?

This quote is attributed to Parmenides.

To think truly is to think of what is, and nothing else. - Parmenides

"To think truly is to think of what is, and nothing else."

Parmenides Knowledge

Philosopher Ancient Greece 515–445

"What is, is. What is not, is not."

"Being is; not-being is not."

"One should both say and think that Being is."

"How could what is perish? How could it come to be?"

"We're not just after treasure. We're preserving history."

"The mind is humanity's greatest tool."

"A tidy room reflects a tidy mind."

"You can learn a lot about a person by how they keep their space."