Opinion amongst modern historians is also split; for instance, Fine accepts the concept of the Peace of Callias, whereas Sealey effectively rejects it. Holland accepts that some kind of accommodation was made between Athens and Persia, but no actual treaty. Fine argues that Callisthenes's denial that a treaty was made after the Eurymedon does not preclude a peace being made at another point. Further, he suggests that Theopompus was actually referring to a treaty that had allegedly been negotiated with Persia in 423 BC. If these views are correct, it would remove one major obstacle to the acceptance of the treaty's existence. A further argument for the existence of the treaty is the sudden withdrawal of the Athenians from Cyprus in 449 BC, which Fine suggests makes most sense in the light of some kind of peace agreement. On the other hand, if there was indeed some kind of accommodation, Thucydides's failure to mention it is odd. In his digression on the "pentekontaetia", his aim is to explain the growth of Athenian power, and such a treaty, and the fact that the Delian allies were not released from their obligations after it, would have marked a major step in the Athenian ascendancy. Conversely, it has been suggested that certain passages elsewhere in Thucydides's history are best interpreted as referring to a peace agreement. There is thus no clear consensus amongst modern historians as to the treaty's existence.