The discovery of Gunpowder drove a massive investment in metallurgy as nations sought to develop more dependable and more accurate gun barrels. As often is the case, this research borrowed heavily from non-military fields. Turning to the reverberatory furnace (a coal furnace developed in the 17th century for glassmaking) to cast the iron, nations were able to make stronger, lighter iron cannons. These cannons replaced their bronze barreled predecessors, and artillery gained further prominence on the battlefield.