Reconstruction of the Achaemenid "falcon standard",  based on the design of a tile of Egyptian blue frit found at Persepolis in 1948 (Īrān-Bāstān Museum, Tehran, no. 2436), with the addition of coloring.
The plaque shows Egyptian Horus, but in the Persian context was likely associated with the Avestan  "glory-bringing bird", varəγna.
Literature: Sāmī, Persepolis, tr. R. Sharp, Shiraz, 1970, fig. facing p. 100; H. Luschey, "Ein königliches Emblem," AMI 5, 1972, pp. 257-60. A. Shapur Shahbazi, DERAFŠ, Encylopedia Iranica (1994).

The standard is described by Xenophon in Cyropaedia (Book VII, C.1) as: "...and the word went down the lines, "Eyes on the standard and steady marching!". The standard was a golden eagle, with outspread wings, borne aloft on a long spear-shaft, and to this day such is the standard of the Persian king." (however here he is describing Artaxerxes II's standard at Cunaxa).
Own work, Based on a photograph hosted at iranica.com (it is our understanding that this photograph shows a reconstruction and not the actual artefact from Persepolis).
Sodacan