We cannot trace with any exactness the course of these events, during the nineteen months between Alexander’s accession and his landing in Asia (August 336 B. C., to March or April 334 B. C.) We learn generally that Memnon was active and even aggressive on the north-eastern coast of the Ægean. Marching northward from his own territory (the region of Assus or Atarneus skirting the Gulf of Adramyttium[177]) across the range of Mount Ida, he came suddenly upon the town of Kyzikus on the Propontis. He failed, however, though only by a little, in his attempt to surprise it, and was forced to content himself with a rich booty from the district around.[178] The Macedonian generals Parmenio and Kallas had crossed into Asia with bodies of troops. Parmenio, acting in Æolis, took Grynium, but was compelled by Memnon to raise the siege of Pitanê; while Kallas, in the Troad, was attacked, defeated, and compelled to retire to Rhœteium.[179] [177] Diodor. xvii. 7: compare Arrian, i. 17, 9. ἐπὶ τὴν χώραν τὴν Μέμνονος ἔπεμψεν—which doubtless means this region, conquered by Mentor from Hermeias of Atarneus. [178] Diodor. xvii. 7; Polyænus, v. 34, 5. [179] Diodor. xvii. 7. We read also of military operations near Magnesia between Parmenio and Memnon (Polyænus, v. 34, 4). We thus see that during the season preceding the landing of Alexander, the Persians were in considerable force, and Memnon both active and successful even against the Macedonian generals, on the region north-east of the Ægean. This may help to explain that fatal imprudence, whereby the Persians permitted Alexander to carry over without opposition his grand army into Asia, in the spring of 334 B. C. They possessed ample means of guarding the Hellespont, had they chosen to bring up their fleet, which, comprising as it did the force of the Phenician towns, was decidedly superior to any naval armament at the disposal of Alexander. The Persian fleet actually came into the Ægean a few weeks afterwards. Now Alexander’s designs, preparations, and even intended time of march, must have been well known not merely to Memnon, but to the Persian satraps in Asia Minor, who had got together troops to oppose him. These satraps unfortunately supposed themselves to be a match for him in the field, disregarding the pronounced opinion of Memnon to the contrary, and even overruling his prudent advice by mistrustful and calumnious imputations.