1. They believed in the harmonious development of the person through a sound mind, by the practice of athletics.
A. Classical Romans
C. Classical Greeks
B. Bourgeoisie
D. Medieval Knights​

Classical Greeks!

Explanation:

The phrase below has been derived from a latin term for "sound mind, healthy body". It uses references from Hercules which is Greek Mythology.

"You should pray for a healthy mind in a healthy body.

Ask for a stout heart that has no fear of death,

and deems length of days the least of Nature's gifts

that can endure any kind of toil,

that knows neither wrath nor desire and thinks

the woes and hard labors of Hercules better than

the loves and banquets and downy cushions of Sardanapalus.

What I commend to you, you can give to yourself;

For assuredly, the only road to a life of peace is virtue."