Page "Battle of Marathon" Paragraph 33

Whatever event eventually triggered the battle, it obviously altered the strategic or tactical balance sufficiently to induce the Athenians to attack the Persians.

If the first theory is correct ( see above ), then the absence of cavalry removed the main Athenian tactical disadvantage, and the threat of being outflanked made it imperative to attack.

Conversely, if the second theory is correct, then the Athenians were merely reacting to the Persians attacking them.

Since the Persian force obviously contained a high proportion of missile troops, a static defensive position would have made little sense for the Athenians ; the strength of the hoplite was in the melee, and the sooner that could be brought about, the better, from the Athenian point of view.

If the second theory is correct, this raises the further question of why the Persians, having hesitated for several days, then attacked.

There may have been several strategic reasons for this ; perhaps they were aware ( or suspected ) that the Athenians were expecting reinforcements.

Alternatively, since they may have felt the need to force some kind of victory — they could hardly remain at Marathon indefinitely.