In the mean time, however, the forces which he had sent for from Syria had not arrived, and no alternative was left but to defend the capital and himself as well as he could with the very small force which he had at his disposal.
He determined, however, first, to try the effect of orders sent out in Ptolemy's name to forbid the approach of the army to the city.

Two officers were accordingly intrusted with these orders, and sent out to communicate them to Achillas.

The names of these officers were Dioscorides and Serapion.
It shows in a very striking point of view to what an incredible exaltation the authority and consequence of a sovereign king rose in those ancient days, in the minds of men, that Achillas, at the moment when these men made their appearance in the camp, bearing evidently some command from Ptolemy in the city, considered it more prudent to kill them at once, without hearing their message, rather than to allow the orders to be delivered and then take the responsibility of disobeying them.

If he could succeed in marching to Alexandria and in taking possession of the city, and then in expelling Caesar and Cleopatra and restoring Ptolemy to the exclusive possession of the throne, he knew very well that the king would rejoice in the result, and would overlook all irregularities on his part in the means by which he had accomplished it, short of absolute disobedience of a known command.

Whatever might be the commands that these messengers were bringing him, he supposed that they doubtless originated, not in Ptolemy's own free will, but that they were dictated by the authority of Caesar.