Spartans valued discipline, obedience, and courage above everything. If baby Spartan boys weren't healthy they were left to die. Spartan boys were trained to be soldiers at an early age. They weren't given much food or clothes for the winter so they went through many hardships. Spartan men stayed in the army until 60 years old.
Athenians valued education, clear thinking and the arts. Athenian boys trained like the Spartan boys but it wasn't as harsh. Boys from rich families would work to improve their minds with private tutors learning philosophy, geometry, astronomy, etc. They only had to be in the army for 2 years from age 18 to 20.