In 451 or 450 Pericles carried a law confining Athenian citizenship to those of Athenian parentage on both sides. No source provides any background to this proposal; it is not even clear whether it was retrospective.
A high school diploma or GED is enough to get started as an office clerk. It is important to have some office skills, such as typing, good phone skills, word processing, etc. Most training is done on the job.
In most states, court clerks are required to have at least a high school diploma and a certification in this field or a two year college degree. Your education will also determine the type of court you can work in.