Battle was joined across the full line, with only the marshes preventing the whirling, hacking, bloody front spreading too far. Xanthippus fought in grim silence as the light changed with infinite slowness to the paler colours of early evening. He loved that time of day above all others, when the air cooled. He stood with the men of his city and he killed with them, though his knee felt like it was on fire and he could not trust his full weight to it.

Themistocles and Aristides fought well in the centre. On the left, Xanthippus and Epikleos cut Persians down with dark delight, with spears and then blades, going forward in formation to stab and withdraw and take another step. Lunge, pull, block with the shield, go forward. Those who fell under their heels were crushed and gashed until they could not rise again.

The Persians broke, though their king watched them. Xanthippus saw the pavilion coming down before he felt the shift, so that he could not have said which caused the other – whether the king had decided to retreat to his ships and so stolen the heart from his men, or whether the imminent rout forced the Great King to run before he was trapped on the beach.

The battle became a brutal slaughter. Xanthippus found his voice had gone completely, so that Epikleos had to relay his orders to keep discipline. The Immortals could feel the sea at their back as they retreated. In their panelled coats, they could not swim. When they felt waves lapping at their feet, the fighting became utterly desperate. It was then that holding the line of shields proved its worth. The sea frothed with red as Persians fell, slowly tumbling in the waves. A ship accepted their king into its hold and was hauled into deep water. His personal guard stood three deep as it was heaved off the sand, determined to allow him to get free, though they had no ship themselves.

Xanthippus saw Miltiades among the officers who pressed them while they stood in the shallow waters, cutting and battering until the king’s guards had fallen with the rest. He thought the Persians had lost the will to keep fighting by then or they might have done better against weary men. His citizens of Athens fought for more than just a king. Perhaps that was it.

Themistocles took his centre tribes forward in a block to butcher the remaining slingers and archers. They were hard men, Ethiopians and Egyptians with knives and clubs. Yet they died like lambs to hoplites in bronze armour. The killing went on until darkness came – and then Aristides set the last beached ships on fire so they could see. No Persian would be left alive to rob, rape or kill innocents after they had gone.

Bodies bumped against one another as the sea grew calm, like apples on the surface. In the end, it was done, with the moon rising high in the summer evening. Miltiades set guards and sent his herald Pheidippides running back from Marathon to Athens with news of the victory. There would be celebration in every house that night. The women and the elderly, the lame and the sick and the children would give thanks to the gods for being saved.