(Χάρτας) and SYADRAS (Συάδρας), statuaries at Sparta, were the teachers of Eucheirus of Corinth, and he of Clearchus of Rhegium, and he of the great statuary Pythagoras of Rhegium. (Paus. 6.4.2.) Hence it is calculated that Chartas and Syadras flourished about 540 B. C., a little before which time the Spartans sent to Croesus a crater of bronze ornamented with figures. (Hdt. 1.70.)
[P.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890