shields round Castor and the cohort’s standard. More men joined them, roughly jostled into position by Septimus as he made for his commander. Once there were perhaps fifty men formed into a tight circle, with shields raised, Castor shouted the order to retreat along the track towards the cliff. They fell back slowly into the dusk, leaving their wounded comrades who pleaded desperately not to be abandoned to the Parthians. Castor steeled his heart.There was nothing he could do for the injured. The only shelter left to the survivors of the cohort was the partially built fort on the cliff. If they could reach that then there was a better chance of making a final stand. The cohort was doomed, but they would take as many of the Parthians with them as possible.
The small band of auxiliaries reached the foot of the cliff before the enemy realised their intention and came after them in earnest. Horsemen rode out of the darkness to loose their shafts and then reined in and steadily notched and aimed more arrows once they realised there was no further need for hit and run tactics. As the cohort edged up the track they presented a narrow target to the enemy, and a solid wall of shields protected the rear of the small band of survivors as they climbed back up to the construction site. The Parthians followed them, as closely as they dared, shooting arrows the moment a gap opened in the shields. As they realised the futility of trying to shoot through the shields they switched their aim to the unprotected legs of their quarry, forcing them to crouch low and slowing them down as they toiled up the track. Even so, five more men were injured before the track evened out and the small column of auxiliaries reached the perimeter of the site. Up on the cliff the wind was still keen, but they were at least free of the clouds of dust and could see clearly over the billowing sand that blotted out the surrounding landscape.
Leaving Septimus to command the rearguard, Castor led the rest in through the foundations of the main gate. The walls were too low to keep the Parthians out of the fort, and the only place the auxiliaries could make a stand was at the nearly completed watchtower in the far corner of the fort, on the very edge of the cliff.
‘This way!’ Castor bellowed. ‘Follow me!’
They hurried across the maze of straight lines of rocks that marked the locations for the buildings and thoroughfares planned for the fort. Up ahead the bulk of the watchtower loomed against the star-scattered night sky. As soon as they reached the timber-framed structure Castor stood by the entrance and waved his men inside. There were barely more than twenty with him and he knew that they would be lucky if they survived to see the next dawn. Ducking inside, Castor gave orders for the men to man the platform above the tower and the window slots on the floor above the entrance. He kept four soldiers with him to defend the entrance as they waited for Septimus and the rearguard to catch up with them. There was only a brief delay before several dim figures burst through the uncompleted gatehouse and raced towards the watchtower. Moments later a wave of enemy warriors appeared and chased after them with cries of triumph.
Castor cupped a hand to his mouth and shouted. ‘They’re right on you! Run!’
The men of the rearguard were weighed down by their armour and already exhausted from the day’s labour, and they stumbled across the site. One tripped on a loose rock and tumbled to the ground with a shrill cry, but not one of his comrades even paused to look back, and moments later he was engulfed by the wave of Parthians surging towards the watchtower. They swarmed over the fallen auxiliary for a moment, hacking and slashing at him with their curved blades. His death brought his comrades just enough time to reach the watchtower and they piled inside, lowering their shields as they gasped for breath. Septimus licked his lips as he forced himself to straighten