One reason for a proper camp was to protect the men from the scouring winds that howled over the plains of Thessaly. No one fought in winter. Leaving aside the difficulties of supplying food, it was a time for men to return home, to father children on their wives, to sleep and heal. The blood grew thick and full of torpor in cold months, like bears or dormice. In summer and autumn, they worked, tending their lands. In spring, as the blood rose, they went to war. Mardonius yawned, feeling stiff in every joint. Spring seemed a long way off that day.

The sound of hooves and jingling iron jerked him from his reverie. Horsemen coming in. The camp was always busy around him, a true city in the wilderness, created from earth and wood. He heard them even so, looking over in anticipation. Mardonius hoped it was the ones he had summoned in the king’s name. He had expected them for weeks.

The party of riders had to duck to come in under the camp gate – three men in furs and cloaks, one clearly the leader. Mardonius nodded to himself, pleased. They were not Persian. Despite the cold, their legs were bare in the Greek style, legs hanging low, using heels and reins to control their mounts. Yet their horses were bloodlines of Persia, magnificent beasts both stronger and taller than the mounts of Thessaly. The Greeks did not seem to understand the power of horsemen, Mardonius thought sourly. Only foul luck had taken the cavalry from the field at Marathon, or they would have learned very swiftly. He still hoped to teach that lesson before he went home, though as he told his sons, a perfect campaign was one where victory came without a pile of corpses. Not that he minded either way.

Mardonius could almost feel his Immortals bristle as the strangers approached. A hundred bustled up in white coats, halting with their red-faced officer, all too aware of the eye of Mardonius on him. The general hid his sigh. Youngest sons always tried too hard. It was their nature. In response, he praised only sparingly, when the lad really did well.

By the time the Macedonians dismounted, two curved lines of white-coated warriors watched, with Mardonius at the deepest point of the cup. The general made a snap decision. Though he did not know them well, they had proved themselves as friends, both in allowing the passage of the Persian army through their land and in answering his personal call. Mardonius knew he could insist on proper obeisance – on them lying face down before him in the mud. He was, after all, the representative of the imperial throne. Yet his Greek allies always seemed to resent being made to show proper respect. He needed them to work for him, or at least their leader.