Berengar was currently standing in one of his many Nitraries, formed to produce Saltpeter from common manure. It was the primary ingredient in the creation of gunpowder and was very rare in Europe as a naturally occurring substance.
However, with the knowledge he gained from his previous life, which was far more advanced than this world, he knew of a way to create it from manure, ash, plant greens, and of course, cow urine. Though this was an extensive process, and as such, he had been relying on the trade networks throughout to import the material for the use in his militia's weapons.
However, after nearly four months of producing the material, his first batch of homegrown saltpeter was about to come to fruition. Since he initially constructed his industrial district, he had set aside an area to produce potassium nitrate, also known as saltpeter.