There has been an assumption in the scholarly literature about Emperor Hadrian ' s meeting with a Parthian king in about 123 CE. This assumption, based on a single passage in a source whose veracity and reliability has repeatedly been questioned, cannot be proved and appears to be false. However, Hadrian ' s summit has been accepted without question as a fact in many scholarly books, although some authors chose to ignore this doubtful event. In this article, the whole history of Romano-Parthian relations is briefly summed up and the author tries to point out that, in reality, no summit of heads of these two states ever occurred.