In ancient Athens, boys started going to school at about the age of six or seven. They had to go to three different schools – one for sport, one for music, and one for things like reading and writing. If they could afford it, a family also had a special slave called a paidagogos who would accompany their sons to all of their schools, making sure that they were safe, that they turned up and that they behaved.
Boys did physical education at the palaistra, an open field. Men trained there at the same time. You had to take all your clothes off to do any sport. At the palaistra, boys learned javelin, discus, long jump, running, boxing and wrestling.
Every single Greek school was private and the kids' parents had to pay for it. Parents decided how long their sons should stay at school, and that sometimes depended on how much money they had. If a young man wanted to continue his education, and if he could afford it, then he might go to a philosophical school, which was like a college today.
In Sparta, life was very different. Their education was mostly aimed at creating good soldiers, because every male citizen had to serve in the army for most of his life. Citizen boys had to leave home and join the army at the age of only seven.