Before revision: History Early history upCtesibius's clepsydra (3rd century BC) It was a preoccupation of the Greeks and Arabs (in the period between about 300 nbsp; BC and about 1200 AD) to keep accurate track of time.
After revision: History Early history upCtesibius's clepsydra (3rd century BC) It was a preoccupation of the Greeks and Arabs (in the period between about 300 BC and about 1200 AD) to keep accurate track of time.