I think there's even a plausible direct route to stoicism. The Ancient Greeks were entirely aware of the importance of having a healthy body to have a healthy mind. In Ancient Greece, a gymnasium is where one would go not only to train the body, but also the mind. Many countries, such as Germany, have retained this etymology with certain advanced types of schools being called gymnasiums.

And in the gym one can only make significant gains by effectively controlling and overcoming their own response to pain and the body telling you, 'no - stop stop stop!' Why would truly effective control and mastery of our minds be any different? And from there you're already 9/10ths of the way to 'inventing' Stoicism. Somehow this reminds me of a really old (and fun) Arnold interview [1]. His behavior, attitude, and responses there (and even in general, really) really hit on Stoic values.

[1] - https://www.youtube.com/watch?v=bTGPfJUJRh0