 Indeed, most estimates for the total Persian force are generally in this range.For instance, Delbrück, based on the distance the Persians marched in a day when Athens was attacked, concluded that 75,000 was the upper limit for the size of the Persian army, including the supply personnel and other non-combatants.In his battle account of Plataea, Delbrück estimated the Persian army, including allied Greeks, as amounting to 40,000.