On 16 May the attackers sent part of their army around the flank of the Greeks to cut off their line of retreat, but it failed to arrive in time. The next day the rest of their army made a frontal assault. Both sides fought ferociously. The Ottomans were held at bay by the fire of the defending infantry until their left flank defeated the Greek right. The Ottoman formation broke through, forcing a renewed withdrawal. Smolenskis was ordered to stand his ground at the Thermopylae passage but on 20 May a ceasefire went into effect.