On the other, Thrace, with its hills and mines, its farms and villages, its hunters and warriors. Xerxes smiled at the thought. To those primitives, his army must have seemed like statues of gold and iron, like angels walking the earth. The Thracian women were comely enough. A few had been taken up by his officers, though they tended to kill themselves, or occasionally the man who snored alongside.

Xerxes shook his head. It had looked for a time as if the tribes of Thrace would rise up and resist. He had sent imperial messengers to the towns and villages there, giving them a stark choice. Even then, he had been forced to make an example of one gathering of kings determined to refuse his authority. They had not stood a chance against his Immortals. It was all so unnecessary! He had no quarrel with them. Like the boats that groaned under his feet, they were just a bridge to lands beyond. Xerxes smiled at that thought.

Beyond Thrace, the mountains of Macedonia rose like blades on the maps. Persian merchants had visited the towns along his route for years, learning all they could. Xerxes himself had never seen those lands. The kings there were said to be warlike and to field armies of spearmen, clad in bronze like the men of Athens. Xerxes wondered if they would stand in the path of General Mardonius when he marched half a million men through their heartland. They too were the bridge. He cared nothing for Macedon, not that season. Greece was his prize – the Athenians and the Spartans who had scorned him, like a wound that would not heal.

Xerxes listened as the priests invoked his father’s support in heaven. He closed his eyes for a moment, joining the chant in rhythms he knew from childhood. The repetition calmed him, bringing him peace. In the breeze that touched his skin, he thought he could feel his father. More, he thought he could hear the voices of children, laughing and calling to one another.

Xerxes breathed in sharply, filling his lungs with cold air. If the Great King had come to see his son’s creation, Xerxes would carry his spirit as a noble breath – right to the cities of Greece. It was a glorious concept and he felt certainty take hold. Not even the priests would understand, he realised. Other men dreamed, only to see their dreams made dust. Xerxes was not of their kind. His hopes became bridges. His dreams became vengeance, an arrow sent from his father’s bow that had been in flight for a long time. It would land in the heart of Athens.

When the priests had finished and lay quivering on the causeway, Xerxes let them both take his hand, granting them honour. The younger one held on for a beat too long, whispering prayers and benefactions, his mouth wet as he kissed the royal knuckles.

Xerxes reached for the knife on his belt, but the priest had the sense to let go and fall flat. For a long moment, the king looked down on him, considering whether he should bless the bridge in blood. Xerxes could feel spit drying on his hand and it would have been a fitting sacrifice. God stood with him. His wife Amestris had borne him a son and crown prince, named Darius, of course, after his father. That final piece of the plan allowed Xerxes to leave on the campaign at last, his succession secured.