They came at the dead of night, says Caesar.
Julius Caesar (public domain photo)
He couldn’t have liked that much. Darkness always greatly increased the danger of battle. His lookout towers had a fine view of the enemy during the day and he could watch a battle as on a map. But at night he was as blind as any of his soldiers and could do little to help them once the attack came. The good part was that night would increase the effectiveness of his “minefields” and trenches in front of the wall.
A reconstructed section of the Alesia investment fortifications (Creative Commons Attribution-Share Alike 3.0 Unported license photo)
There were three trenches. The first was twenty feet wide and 400 paces from his wall. He had dug it while raising the wall, precisely to give protection to the soldiers while they worked. At that distance the enemy would not be able to hurl lances and stones with much effectiveness. Later he dug two more ditches and filled one of them with water by making a channel from the creek that flowed around Alesia.
The trench under the wall was slightly slanted away from the wall to make it difficult to stand scaling ladders; and at the joints where the logs of the wall were driven into the mound of earth, Caesar drove in large pointed stakes. “These would slow down an ascent,” he wrote in his plain, undramatic style. The wall was equipped with battlements and there were towers every eighty feet.
These defences had at first seemed sufficient but later Caesar decided to add to them. He had to give his soldiers greater protection.
They had to range wide outside the camp to find not only food and timber but also stones to be used as ammunition for the artillery. While they were out the walls were very weakly manned and Caesar feared an attack. So he decided to strengthen his defences with traps and “minefields”. Some of these were his own invention, some the improvisation of his soldiers as they worked. Because Caesar wrote about them, they have become famous.
The soldiers gave them names. “Gravestones” were sharpened branches fixed solidly at the bottom of a long trench five feet deep. There were five rows of them to a trench. “Anyone who made his way onto them would be impaled,” says Caesar.
“Lilies” were funnel-shaped pits spread out in patterns of five (quincunx). At the bottom of each was a log as thick as a man’s thigh, sharpened to a fine point and tempered in the fire. Earth was packed in around the base of the stake, then the rest of the pit was filled with twigs and brushwood to camouflage it. Eight rows of these lily-pits were dug at three-foot intervals. “Don’t they look a little like flowers?” said the soldiers, admiring their work; and from then on called them “lilies”.
In front of the field of “lilies”, scattered all over here and there and half-buried, were the “spurs”. Those were foot-long logs bristling with iron hooks.
Now at midnight the Gauls, thousands of them, silently moved out of their camp and marched towards Caesar’s wall. Along with their weapons—their slings and bows and swords—they carried wicker hurdles to fill in the ditches. Of the booby traps they knew nothing.
With a loud cry they opened fire and sent a great storm of stones and arrows at Caesar’s soldiers atop the wall.
The cry was also a signal to Vercingetorix, who had been waiting in Alesia, to begin his own sortie and attack on Caesar’s inner wall.
While they were still a few hundred yards from the wall they had a clear advantage in firepower. They showered the walls with missiles.
But when they came closer they fell into the gravestones and lilies and were transfixed; and they stumbled onto the spurs and were impaled. The terrain outside Caesar’s wall became a field of horrors for them and kept back all but the bravest.
A reconstructed Roman ballista (Creative Commons Attribution-Share Alike 3.0 Unported license photo by Scigeek)
The Roman soldiers were ready for the attack, thanks to Caesar’s foresight. Each knew what to do and set to work at his catapult or ballista, ignoring the shower of missiles as best he could. They sent out their own steady hail of heavy stones and iron arrows into the darkness.
The fighting lasted all night. Caesar had to rely on his men and the walls and traps they had made—he had no way of knowing if the defences were being pierced along the kilometers of wall.
When dawn finally came the Gallic general Commius, who had suffered as much uncertainty as Caesar, called a halt to his attack because he was afraid the Romans might make a sudden sortie and encircle his exposed flank. Then he ordered a retreat.
Vercingetorix’s men had been able to fill in the first trench in front of Caesar’s wall on their side, but it took them so long that the fighting was over before they could scale the wall. Disheartened, King Vercingetorix ordered his troops back to Alesia.
The Romans had won this second engagement, round two. Caesar could feel pleased: “Casualties were heavy on both sides,” he wrote, “but there was no breach in the defences.” It was a wonderful achievement.
Yet he knew he was still in grave danger—perhaps graver danger than ever. Much of his ammunition was used up, he had many casualties, and all his soldiers were exhausted. Another attack would be harder to repel. He was still greatly outnumbered. Time, which had run in his favor during the siege, might well start to work against him.
Read Caesar’s Greatest Battle (Part 4) to see how Caesar won but almost lost the Battle of Alesia
Return to Caesar’s Greatest Battle (Part 1)