Your lecturer obviously wasn't familiar with Sappho! She was a female poet born approx 630 BC, died approx 570 BC, so a good guess for this is that it was composed around 600 BC. She lived on the Greek island of Lesbos. Yes, this is where the term Lesbian came from - male and female homosexuality were perfectly normal and usual in Ancient Greece. Probably used as a way to help ensure that when a woman became pregnant her husband could be sure the baby was his. Both men and women had very intense emotional and sexual relationships with friends of the same sex, because men and women were kept strictly apart outside the home and marriage was arranged, but you could associate freely with people of your own sex.
We know a lot more about Sappho in the last few decades because papyri discovered in Egypt, perfectly preserved in the hot dry conditions in the desert, have turned out to have fragments of her poetry written on them. Prior to that, we just had a few fragments preserved since ancient times (same goes for many male poets, to be fair).
However, this lyric poem has been known continuously for the last 2600 years, as it is such a stunning evocation of what it's like to be in love. (Lyric poem no. 31).
"That man seems to me to be equal to the gods
who is sitting opposite you
and hears you nearby
speaking sweetly
and laughing delightfully, which indeed
makes my heart flutter in my breast;
for when I look at you even for a short time,
it is no longer possible for me to speak
but it is as if my tongue is broken
and immediately a subtle fire has run over my skin,
I cannot see anything with my eyes,
and my ears are buzzing
a cold sweat comes over me, trembling
seizes me all over, I am paler
than grass, and I seem nearly
to have died.
but everything must be dared/endured, since (?even a poor man) ..."