It is not explicitly stated by Plutarch, but it has been assumed that the two phalanxes engaged each other during the battle. If this was the case, then the Antigonid strategy would have been for Demetrius to take his cavalry and attack the rear of the allied phalanx; or alternatively, return to station on the right wing and protect the Antigonid phalanx's flank. However, Demetrius found himself unable to return to the battlefield because of the deployment of 300 elephants in his path. The ancient sources repeatedly emphasise the effect of elephants on horses, which are alarmed by the smell and noise of elephants and are loath to approach them. Demetrius would not have been able to take his horses through the line of elephants, nor manoeuvre around such a large quantity of elephants. This 'elephant manoeuvre' was the decisive moment in the battle, but it is not clear how it came about; Plutarch only says that "the elephants were thrown in his way". If the elephants had indeed been held in reserve, then it might have been relatively straightforward to deploy them, but as discussed, it is not clear why so many elephants would have been held in reserve. However, it is also possible that the deployment of the elephants was a piece of improvisation during the battle, though moving such a large number of elephants in such a coordinated manoeuvre in the middle of the battle would have been difficult. Since he was the only allied commander with significant experience of handling elephants, it has been assumed that Seleucus was responsible for this manoeuvre.