Actually, rather common, though not exactly like their use in the CW or WWI of course. I had to Google this to learn, but...
T
rench warfare and the use of defensive ditches were common in antiquity and throughout history before the 1800s, serving as key tactical tools in sieges and field fortifications. While not identical to the extensive, static, machine-gun-heavy systems of World War I, trenches were used for protection against ranged weapons (arrows, early cannons) and to secure positions.
Key examples before the 1800s include:
- Antiquity: The Romans frequently dug entrenched camps nightly when on the move, and, for example, Julius Caesar used trenches surrounding fortifications. The 413 BC Siege of Syracuse involved digging trenches.
- Early Middle Ages: The Battle of the Trench (627 AD) involved digging a trench to defend Medina.
- 17th Century: Sebastien Le Prestre de Vauban, a French engineer, formalized the use of "sapping" and siege trenches (or "zig-zagging" trenches) to allow attackers to approach fortress walls.
- Pre-1800s Defensive Tactics: Trenches were used during the Piedmontese Civil War (1640) and to strengthen positions in the American Civil War.
While used for thousands of years, these trenches were generally used to either protect a temporary camp, defend a fortress, or approach a fortress in a siege rather than forming hundreds of miles of static, permanent, and continuous front lines as seen in WWI.