Well, I didn't think they had strong acids until the 18-19thC, but I was wrong.
http://www.nidlink.com/~jfromm/lavoisier.htmThe word acid comes from the Latin word acere, which means "sour." All acids taste sour. Well known from ancient times were vinegar, sour milk and lemon juice.
Early in the 1200s, the strong mineral acids were first isolated. Sulfuric acid was made by heating green vitriol [iron(II) sulfate] and condensing the vapor into water. Other vitriols gave the same product. Mixing a vitriol with nitre (postassium nitrate) and heating produced vapors which gave nitric acid. Adding sal ammoniac (ammonium chloride) to nitric acid gave aqua regia, so named for its ability to dissolve gold. Hydrochloric acid ("spirit(s) of salt" - a name still used in commerce/pharmacy as late as the early 1970s) also was known to the middle ages; certainly it was known to Paracelsus (early 1500s).
The word alkaline comes from the Arabic al-qily, which means "to roast in a pan" or "the calcinated ashes of plants." By leaching the ashes with water, one can obtain a solution of sodium or potassium carbonate (to use the modern terms). This is then mixed with slaked lime (calcium hydroxide) and you get a solution of NaOH or KOH. This technique was described in writing in the 900s, but may have existed for many years prior.
However, it was not until more modern times that the chemical nature of acids and bases began to be explored.
) and on the cover it shows a sword recovered from the Tomb of Sancho IV the Brave of Castile. He died c 1285, and his tomb was opened in 1923, and the sword was photographed, so it is unlikely that it was modified since his death.