Including earth, how many planets were the ancient Greeks aware of?

The development of astronomy by the Greek astronomers is considered, by historians, to be a major phase in the history of astronomy. The ancient Greeks referred to the planets as "wanderers", the literal meaning of "planet", as a result of what they could see in the sky. From what they could see with the naked eye, the planets appeared to wander, or travel, across the sky each night and on varying paths, during the course, of each year.

The stars in the night sky stay fixed, relative to each other. The planets are all moving around the sun at different rates, so they are not fixed against the stars - they appear to wander over time.

The ancient Greek astronomers were aware of 5 planets six if you include Earth. To really see the other two you needed a telescope. The planets they knew were: Mercury, Venus, Mars, Jupiter, Saturn, and, of course Earth. All these are easily visible to the naked eye and can be seen to move against the background of the stars.