Soldiers again, I wouldn't have believed it.
Although it seems that the Egyptians used them in religious ceremonies so as not to get their feet dirty with blood (horror!), the first who are officially cited as the inventors of heels are those who introduced them into the uniform (of cavalry) they are the ancient Persians.
https://en.wikipedia.org/wiki/High-heeled_shoe#History
I take this opportunity to show you a frieze with Persian fighters (the immortals) slightly modified (the theme ;) ) so that it is not so monotonous.
https://en.wikipedia.org/wiki/Immortals_%28Achaemenid_Empire%29