Wealthier families had private tutors in their homes. These tutors may have  been educated slaves, having obtained a good education in their homelands before having been captured during war times and sold as slaves. 





Vegetius writing in the late fourth century AD remarks on the need for some of the legionaries to be able to read and write. The army may have required a higher level of basic literacy due to the tasks that some would have to carry out. Vegetius refers to to the first cohort in a legion which surpasses the others in number and quality, including literacy(6).

Vegetius, Handbook of Military Matters 1.2.6,19,20

https://archive.org/details/pdfy-sOkC3FmoLlr4C6zz/mode/2up



LINKS for "EDUCATION"


Quintilian Institutio Oratoria. English translation by H.E. Butler. Vol. I. Books I-III

https://archive.org/details/english-translation-of-quintilianus-by-butler.-volume-i.-books-i-iii.-loeb./page/n3/mode/2up