of Corinth and TELE'PHANES of Sicyon, were, according to Pliny (35.5), the first artists who practised the monogram, or drawing in outline with an indication also of the parts within the external outline, but without colour, as in the designs of Flaxman and Retzsch. Pliny, after stating that the invention of the earliest form of drawing, namely, the external outline, as marked by the edge of the shadow (umbra hominis lineis circumducta, or pictura linearis), was claimed by the Egyptians, the Corinthians, and the Sicyonians, adds, that it was said to have been invented by Philocles, an Egyptian, or by Cleanthes, a Corinthian, and that the next step was made by Ardices and Telephanes, who first added the inner lines of the figure (spargentes lineas intus).
[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