Lysippos See Perseus web site, under Andrew Stewart, One Hundred Greek Sculptors: Their Careers and Extant Works: The Sculptors: The Fourth-century Virtuosi IV. Lysippos

J.J. Pollitt, Art of Greece (1965) p. 145, and Stewart, T124:
Pliny the Elder, Natural History 34.37, 34.61 and 34.65
(37) Lysippus is related to have made 1,500 works, all of them of such artistic quality that any single one could have given him fame; this number came to light upon his death, when his heir broke open his strong-box. For it was his custom to put in it one gold coin, worth a denarius, from the fee which he received for each statue.
(61) Duris says that Lysippus of Sicyon was nobody's pupil; originally a bronze-smith, he joined the discipline after hearing a response from the painter Eupompus. When asked which of his predecessors he followed, Eupompus pointed to a crowd of people and said that it was Nature herself, not another artist, whom one should imitate.
(65) Lysippus is said to have contributed much to the art of sculpture, by rendering the hair in more detail, by making the heads of his figures smaller than the old sculptors used to do, and the bodies slenderer and leaner, to give his statues the appearance of greater height. Latin has no word for the symmetria which he most scrupulously preserved by a new and hitherto untried system that modified the foursquare figures of the ancients; and he used to say publicly that while they had made men as they were, he made them as they appeared to be. A distinguishing characteristic of his is seen to be the scrupulous attention to detail maintained in even the smallest particulars.