Even during the 4th century BC the idea of the treaty was controversial, and two authors from that period, Callisthenes and Theopompus appear to reject its existence. It is possible that the Athenians had attempted to negotiate with the Persians previously. Plutarch suggests that in the aftermath of the victory at the Eurymedon, Artaxerxes had agreed a peace treaty with the Greeks, even naming Callias as the Athenian ambassador involved. However, as Plutarch admits, Callisthenes denied that such a peace was made at this point (c. 466 BC). Herodotus also mentions, in passing, an Athenian embassy headed by Callias, which was sent to Susa to negotiate with Artaxerxes. This embassy included some Argive representatives and can probably be therefore dated to c. 461 BC (after forging of the alliance between Athens and Argos). This embassy may have been an attempt to reach some kind of peace agreement, and it has even been suggested that the failure of these hypothetical negotiations led to the Athenian decision to support the Egyptian revolt. The ancient sources therefore disagree as to whether there was an official peace or not, and if there was, when it was agreed. 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 450 BC, which 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.