The story is told in Pliny Nat. Hist. 7.37.125. Similar stories about Alexander appear in Plutarch Moralia 335, Horace Epist. 2.1.239ff., Valerius Maximus 8.11.2, Arrian Anabasis 1.16.4. Pyrgoteles is otherwise unknown; the Life of Alexander and Plutarch call this third artist Stasicrates; Vitruvius 2 praef. calls him Deinocrates, Strabo 14.1.23 Cheirocrates.