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.
Records clerks generally need at least a high school diploma or equivalent. Receptionist, secretary, and customer service experience may be beneficial; healthcare experience may or may not be required, but records clerks must be able to understand the terminology used by healthcare staff.