# How would you make/produce sulfuric acid with tools only the romans had?

I have been reading about sulfuric acid and its other compounds the romans had, yet I don't understand how they where getting sulfur rich compounds and how they convert it to sulfuric acid. Was it from the volcanoes around them, or was it from sulfur rich rocks/mineral deposits?

There are several naturally occurring sulfate minerals such as copper(II) sulfate (pentahydrate mineral name: chalcanthite) that will decompose into $\ce{SO3}$ when heated to a few hundred degrees, which produces sulfuric acid when dissolved in water. These compounds were known as vitriols due to their glassy appearance and sulfuric acid was known as oil or spirit of vitriol since it was derived from these minerals. Chalcanthite seems to be a natural oxidation product of copper deposits. Copper(II) sulfate in particular was known as Roman vitriol, but I don't know if this means that that was the primary source for the Romans.