Final answer:
Gunpowder and guns were developed in China and spread through trade routes and Mongol invasions. They were introduced to Western Europeans through the Crusades and to the Middle East by the Mongols. Gunpowder and firearms technology greatly influenced military advancements in various regions.
Step-by-step explanation:
The development of gunpowder and guns can be traced back to China, where it was first invented by Chinese alchemists in the 9th century. Gunpowder and firearms technology then spread in different directions. They were introduced to Western Europeans through trade routes and through knowledge gained during the Crusades. In Russia, gunpowder and early versions of firearms were brought by the Mongols from China. In the Middle East, gunpowder and its use in weapons were introduced by the Mongols and adopted by Arab and Turkic forces. The Ottoman Empire, Safavids in Iran, and the Mughals in India were among the Islamic states that used and improved upon gunpowder weapons.