CARNUNTUM ( in Ptolemy), an important Roman fortress, originally belonging to Noricum, but after the 1st century a.d. to Pannonia. It was a Celtic town, the name, which is nearly always found with K on monuments, being derived from Kar, Karn ("rock," "cairn"). Its extensive ruins may still be seen near Hainburg, between Deutsch-Altenburg and Petronell, in lower Austria. Its name first occurs in history during the reign of Augustus (a.d. 6), when Tiberius made it his base of operations in the campaigns against Maroboduus (Marbod). A few years later it became the centre of the Roman fortifications along the Danube from Vindobona (Vienna) to Brigetio (O-Szöny), and (under Trajan or Hadrian) the permanent quarters of the XIV legion. It was also a very old mart for the amber brought to Italy from the north. It was created a municipium by Hadrian (Aelium Carnuntum). Marcus Aurelius resided there for three years (172-175) during the war against the Marcomanni, and wrote part of his Meditations. Septimius Severus, at the time governor of Pannonia, was proclaimed emperor there by the soldiers (193). In the 4th century it was destroyed by the Germans, and, although partly restored by Valentinian I., it never regained its former importance, and Vindobona became the chief military centre. It was finally destroyed by the Hungarians in the middle ages.
A special society (Carnuntumverein) exists for the exploration of the numerous ruins, the results of which will be found in J.W. Kubitschek and S. Frankfurter, Führer durch Carnuntum (3rd ed., 1894); see also E. von Sacken, "Die römische Stadt Carnuntum," in Sitzungsberichte der k. Akad. der Wissenschaften, ix. (Vienna, 1852); article by Kubitschek in Pauly-Wissowa's Realencydopadie, iii. part ii. (1899); Corpus Inscriptionum Latinarum, iii., part i. p. 550.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)