This first athenian reform leader established the citizen's assembly, forbade enslavement for debts, and made fathers responsible for seeing that their sons learned a trade.
peisistratus
solon
cleisthenes
xerxes

It was Solon.  Apart from these reforms, Solon also gave poor citizens the right to vote and also created a court of appeals. This was composed citizens from all social classes who examine cases of lower courts.  All citizens were allowed to attend the General Assembly and revised the Code of Laws of Athens.  Apart from political reforms, he instituted economic reforms as well. He provided different jobs for those can’t farm such as trades and professions. He also introduced new measures and weights.