Who bought black powder to Europe?

It is believed that black powder was brought to Europe by the Mongols, who invaded and conquered parts of Eastern Europe in the 13th century. The Mongols had been using black powder in warfare for several decades, and it is thought that European soldiers and scholars first encountered the substance during battles with the Mongols.
Another theory is that traders and travelers from the Middle East who had come into contact with black powder in the Islamic world, brought it back to Europe.
It is also possible that black powder was independently discovered in Europe, as the ingredients needed to make it were readily available, but the evidence of this is not clear. Regardless of the origin, it's certain that it was used in Europe soon after it was invented in China.