For many years, it was accepted fact that the Chinese were the first to develop black powder. It was also widely believed that they used black powder as a propellant by the 10th century. However, some recent research revealed inconclusively that black powder might actually have been developed earlier in Arabia.
Notwithstanding, others theorize that Roger Bacon, the English Alchemist and Friar, invented black powder. It is known that he wrote instructions for its preparation in the mid-1200s. It is also known that Bacon could read Arabic, so it is possible that he obtained the formula from Arabs.
A seemingly less-plausible theory credits another monk and alchemist, the German Berthold Schwarz, with discovering gunpowder around 1313 AD. Records of this are somewhat sketchy as well as those that sometimes credit him with being the first European to cast bronze cannon.
Nevertheless, verifiable records indicate that black powder was used in Europe by 1247, during the siege of Seville during the Moorish Wars in Spain.
In light of all of these theories, it is, therefore, impossible to conclude with any certainty where-or-when black powder was developed or fist used.