Siege Trenches in the English Civil War

A cross section of a parallel trench as dug by an attacker. The spoil heap and gambion hid the men in the trench from view and protected them against incoming bullets.

Since it was clearly impossible to march across the cleared killing field, the first move of any attacking commander was to find another way. That meant digging trenches. The first trench to be dug was the First Parallel. This was dug parallel to the defensive wall to be assaulted, hence its name. It was positioned right at the maximum range of the cannon on the walls. The main purpose was to conceal the movements of the attacking troops from the watchers on the defences, though it was also proof against cannonballs and so provided real shelter for the men.

The digging of trenches was a skilled and arduous business. Generally a team of five skilled men was employed, with a dozen or more unskilled men attached to do the heavy lifting work. The first men crawled forwards on hands and knees protected behind a heavy wooden shield that was mounted on wheels. The shield was pushed forward a few inches, then wedged in position. Behind it the men dug a trench about a foot deep and two feet wide. The earth from this was piled into a large wickerwork basket called a gabion. When packed with earth a gabion was strong enough to withstand bullets or small cannonballs. Once the this was done, the shield was pushed forward a bit further and the process began again.

Meanwhile a second team moved in to do more digging, deepening the trench to around two feet and widening it to three feet. The earth was likewise piled up into the gabion. The third team enlarged the trench further and completed the filling of the gabion. A fourth team arrived to deepen the trench so much that a man could walk along it in safety without bending down. The spare earth was thrown over the top of the gabion to form a spoil heap to protect its front. The fifth team widened the trench to be about six feet wide so that men could pass each other without difficulty, the earth being also thrown over the gabions. The trench was often finished off by having fascines of twigs piled up on top of the gabions to make it difficult for men from the besieged fortress to launch surprise raids on the trenches.