CARNUNTUM, an important Roman fortress (Kapvovs in Ptolemy), 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 in lower Austria. It was a very old mart for the amber brought to Italy from the north. During the reign of Augustus (A.D. 6), Tiberius made it his base in the campaigns against Maroboduus (Marbod) . Later it became the centre of the Roman defences of the Danube from Vindobona (Vienna) to Brigetio (O-Szony), and (under Trajan or Hadrian) the perma nent quarters of the XIV. legion. It was created a municipium by Hadrian (Aelium Carnuntum) . Marcus Aurelius resided there (I 72-175 ) during the war against the Marcomanni, and wrote part of his Meditations. Septimius Severus, governor of Pannonia, was proclaimed emperor there (193) . In the 4th century it was destroyed by the Germans, and though it was partly restored by Valentinian I., Vindobona became now the chief military centre. It was finally destroyed by the Hungarians in the middle ages.