IA′DERA (Ἰάδερα, Ptol. iii. 16. § 10; Ἰάδαρα, Nicet. p. 348; Iadera, Plin. iii. 26; Iader, Pomp. Mela, ii. 3. § 13; Pent. Tab.; Geog. Rav.; on the orthography of the name see Tzchucke, ad Melam, l.c. vol. ii. pt. 2. p. 275: Eth. Iadertinus, Hirt. B. A. 42. Zara), the capital of Liburnia in Illyricum. Under Augustus it was made a Roman colony. ("Parens coloniae," Inscr. ap. Farlati, Illyr. Sacr., vol. v. p. 3; comp. Ptol. l.c.) Afterwards it bore the name of Diodora, and paid a tribute of 110 pieces of gold to the Eastern emperors (Const. Porph. de Adm. Imp. 30), until it was handed ovey, in the reign of Basil the Macedonian, to the Slavonic princes. Zara, the modern capital of Dalmatia, and well known for the famous siege it stood against the conibined French and Venetians, at the beginning of the Fourth Crusade (Gibbon, c. lx.; Wilken, die Kreuzz. vol. v. p. 167), stands upon the site of Iadera. Little remains of the ancient city; the sea-gate called Porta di San Chrysogono is Roman, but it seems likely that it has been brought from Aenona. The gate is a single arch with a Corinthian pilaster at each side supporting an entablature.

Eckhel (vol. ii. p. 152) doubts the evidence of any coins of Iadera, though some have been attributed to it by other writers on numismatics. (Sir G. Wilkinson, Dalmatia and Montenegro, vol. i. p. 78; J. F. Neigebaur, Die Sudslaven, pp. 181-191.) [ E. B. J. ]