this is interesting and really cute, but without context it's meaning remains cryptic. I.e. I'd really like to know where he was taught, what family he came from, etc.
The article mentions high degree of literacy in the population, but I don't think (public) schools were a thing then. So my best guess is about military service as a civil duty and literacy as part of early childhood military education. Not to say conditioning. I find that thought too pessimistic, anyhow. But jolly peasents engaged in vocational exercise doesn't strike me as very common for the time.
No, it was religious education. I don't know the exact situation in Novgorod at the time, but throughout Europe in urban or near-urban areas it was common for first sons to inherit the family business, while subsequent sons would undertake some sort of religious training, either monastic or not.