Once siege guns were developed, the techniques for assaulting a town or fortress became well known and ritualized. The attacking army would surround a town. Then the town would be asked to surrender. If they did not comply, the besieging army would surround the town with temporary fortifications to stop sallies from the stronghold or relief getting in. The attackers would next build a length of trenches parallel to the defenses (these are known as the "first parallel") and just out of range of the defending artillery. They would dig a trench (known as a forward) towards the town in a zigzag pattern so that it could not be enfiladed by defending fire. Once they were within artillery range, they would dig another parallel (the Second Parallel) trench and fortify it with gun emplacements. This technique is commonly called entrenchment.
Once siege guns were developed, the techniques for assaulting a town or fortress became well known and ritualized. The attacking army would surround a town. Then the town would be asked to surrender. If they did not comply the besieging army would surround the town with temporary fortifications to stop sallies from the stronghold or relief getting in. The attackers would next build a length of trenches parallel to the defenses (these are known as the "first parallel") and just out of range of the defending artillery They would dig a trench (known as a forward) towards the town in a zigzag pattern so that it could not be enfiladed by defending fire. Once they were within artillery range, they would dig another parallel (the Second Parallel) trench and fortify it with gun emplacements. This technique is commonly called entrenchment.