I am trying to write a song with lyrics by Plato (the Greek philosopher). Give me a cord progression that Greeks loved to use and write philosophical lyrics. The song will be played on the piano and a sad melancholic singer is going to provide the vocals.
For the chord progression, a commonly used one in traditional Greek music is the Dorian mode. The Dorian mode is a type of musical scale with a sad and melancholic character, making it a good choice for the mood of your song. A simple Dorian chord progression that you could use for your song might look like this:

| C | D | E flat | F | G | A flat | B flat | C |
| Dorian | Dorian | Phrygian | Dorian | Dorian | Aeolian | Locrian | Dorian |

For the lyrics, you could consider using quotes or themes from Plato's works that reflect his philosophical views. Some potential sources for lyrics could include The Republic, The Symposium, or The Phaedo. Here is an example of a verse and chorus inspired by Plato's philosophy:

Verse 1:
In this world of shadows, what is real?
A journey to truth, that's what I feel
The Forms above, they guide me home
Where knowledge and beauty are never alone.

Chorus:
Oh, philosophy, my guiding light
In this world of darkness, you make everything right
Through the trials and tribulations, you show me the way
To the truth, to the beauty, to the eternal day.

This is just one example of how you could incorporate Plato's philosophy into the lyrics of your song. Feel free to use these lyrics as a starting point or write your own based on Plato's works and ideas.
I want to give the song a more authentic Greek feel. What are some instruments that would have been used when Plato was alive and where might I be able to buy them? Also are there any other stylistic quirks or oddities about ancient Greek music that might make the song sound more unique?
Some authentic instruments from ancient Greece that you could use in your song include:

- Aulos - a double-reed instrument similar to a oboe, often used to accompany singing or poetry recitals
- Lyre - a stringed instrument similar to a small harp, considered a noble instrument and used in education
- Kithara - a larger stringed instrument, similar to a lyre butwith thicker strings and a deeper sound

These instruments can be purchased from specialty music stores or luthiers that create replicas of ancient instruments. Some other characteristics of ancient Greek music to incorporate:

- Use of modes like Dorian, Phrygian, and Mixolydian which have distinctive sounds
- Focuses on melody rather than harmony, with instrumental accompaniment and solo sections featuring virtuosic playing
- Lyrics were an important part, with poetry played an integral role in performance
- Rhythms tended to be relatively simple, based on poetic meter

Incorporating some of these elements into your song can help give it a more authentic Greek feel and reflect the music of Plato's time. The melody, modes, and instrumental accompaniment in particular can help capture the melancholy and philosophical character you described.