The likelihood is that these were the Theban "loyalists", who unlike the majority of their fellow citizens, objected to Persian domination. They thus probably came to Thermopylae of their own free will and stayed to the end because they could not return to Thebes if the Persians conquered Boeotia. The Thespians, resolved as they were not to submit to Xerxes, faced the destruction of their city if the Persians took Boeotia. However, this alone does not explain the fact that they remained; the remainder of Thespiae was successfully evacuated before the Persians arrived there. It seems that the Thespians volunteered to remain as a simple act of self-sacrifice, all the more amazing since their contingent represented every single hoplite the city could muster. This seems to have been a particularly Thespian trait – on at least two other occasions in later history, a Thespian force would commit itself to a fight to the death. At dawn, Xerxes made libations, pausing to allow the Immortals sufficient time to descend the mountain, and then began his advance. A Persian force of 10,000 men, comprising light infantry and cavalry, charged at the front of the Greek formation. The Greeks this time sallied forth from the wall to meet the Persians in the wider part of the pass, in an attempt to slaughter as many Persians as they could. They fought with spears, until every spear was shattered, and then switched to "xiphē" (short swords). In this struggle, Herodotus states that two of Xerxes' brothers fell: Abrocomes and Hyperanthes. Leonidas also died in the assault, shot down by Persian archers, and the two sides fought over his body; the Greeks took possession. As the Immortals approached, the Greeks withdrew and took a stand on a hill behind the wall. The Thebans "moved away from their companions, and with hands upraised, advanced toward the barbarians..." (Rawlinson translation), but a few were slain before their surrender was accepted. The king later had the Theban prisoners branded with the royal mark. Of the remaining defenders, Herodotus says:   The pass at Thermopylae was thus opened to the Persian army, according to Herodotus, at the cost to the Persians of up to 20,000 fatalities. The Greek rearguard, meanwhile, was annihilated, with a probable loss of 2,000 men, including those killed on the first two days of battle.