Although infantry already excel against buildings, the rulers of some nations developed a way to knock them down faster: they hired sappers from the civillian ranks, also calming the complaints of peasants not to be selected for the feudal levy. In real life, they dug tunnels under buildings, collapsing them, a tactic that worked especially well against castles with square keeps. In the game, this technology simply increases the attack bonus of peasants by a whopping +15, giving them +18 vs. wooden buildings, +21 vs. stone buildings, and a legitimate combat use.
Researched at: Castle
Cost: 400 Food , 200 Florins
Effect: Peasants +15 attack against buildings.