Pro Bono Life then and now

Instruction in the elementary school, the Ludus Litterarius, was limited to three subjects; reading, writing , and arithmetic. The teacher (magister) had to depend entirely on the small fees paid him by the parents of his pupils and was often constrained to supplement his income as schoolmaster by other activities. Though the State, in the person of the emperor, became increasingly interested in the support of the distinguished teachers and scholars in the higher realms of learning, there is no evidence of any public contribution to elementary education during the classical period.

Daily Life in Ancient Rome - The People and the City at the Height of the Empire
By Jerome Carcopino, pg.104