The Arena was nominated for the first time in 1996 and ICOMOS (UNSCO's expert advisory body) then stated that the amphitheater is an exceptional and well-preserved example of a large Roman public building and that the overall level of authenticity is undeniable, that is, despite interventions in the 19th century. and the beginning of the 20th century, which were not carried out in accordance with today's conservation principles, the largest part of the entire structure of the original Roman construction.
ICOMOS further asserted the high level of preservation and integrity of the Arena, but refrained from a final assessment and recommended that the decision on inclusion in the World Heritage List be postponed until a comparative study of Roman amphitheaters is completed.
The candidacy was therefore repeated in 1999 under the name 'Antička Pula with amphitheater'. This time, it included, in addition to the amphitheater, other parts of Pula's ancient heritage - the Temple of Augustus, the Sergius Arch, the Double Gate, the Small Roman Theater and early Christian churches from the 4th and 5th centuries.
In the meantime, ICOMOS has prepared a comparative study of several amphitheaters and theaters already inscribed on the World Heritage List and assessed that the Pula amphitheater does not meet the criteria of exceptional universal value. Therefore, he suggested that the nominated cultural property should not be included in the list.