As for the proposed marriage, if he (Alexander) liked to marry a daughter of Darius, he should of course do so, whether her father consented or not.
If Darius wanted merciful treatment, he had better come and deliver himself up at once." The terms of this reply rendered further negotiation impossible.
Darius had probably not hoped much from his pacific overtures, and was therefore not greatly concerned at their rejection.

He knew that the members of his family were honorably and even kindly treated by their captor, and that, so far at any rate, Alexander had proved himself a magnanimous conqueror.

He can scarcely have thought that a lasting peace was possible between himself and his young antagonist, who had only just fleshed his maiden sword, and was naturally eager to pursue his career of conquest.

Indeed, he seems from the moment of his defeat at Issus to have looked forward to another battle as inevitable, and to have been unremitting in his efforts to collect and arm a force which might contend, with a good hope of victory, against the Macedonians.

He replaced the panoplies lost at Issus with fresh ones; he armed his forces anew with swords and spears longer than the Persians had been previously accustomed to employ, on account of the great length of the Macedonian weapons; he caused to be constructed 200 scythed chariots; he prepared spiked balls to use against his enemy's cavalry; above all, he laid under contribution for the supply of troops all the provinces, even the most remote, of his extensive Empire, and asked and obtained important aid from allies situated beyond his borders.