By detaching from Persia and bringing under his own sway the important countries of Syria, Phoenicia, Palestine, Idumsea, and Egypt, he wholly deprived Persia of her navy, and transferred to himself the complete supremacy of the sea, he greatly increased his own resources while he diminished those of the enemy, and he shut out Persia altogether from communication with Greece, excepting through his territories.

He could therefore commence his march into the interior with a feeling of entire security as to his communications and his rear.

No foe was left on the coast capable of causing him a moment's uneasiness.

Athens and Sparta might chafe and even intrigue; but without the Persian "archers," it was impossible that any force should be raised which could in the slightest degree imperil his European dominions.
From Babylon, whither Darius proceeded straight from Issus, he appears to have made two ineffectual attempts at negotiating with his enemy.

The first embassy was despatched soon after his arrival, and, according to Arrian, was instructed merely to make proposals for peace, and to request the restitution of the Queen, the Queen-mother, Sisygambis, the infant prince, and the two princesses, captured by Alexander.