Final answer:
The Crusades lasted for approximately 200 years, from 1096 to 1291, involving a series of religious and political wars primarily between Christians and Muslims with significant cultural and economic impacts.
Step-by-step explanation:
The Crusades continued off and on for approximately 200 years. These series of religious and political wars were primarily fought between Christians and Muslims. Beginning with the First Crusade in 1096, when European Christians aimed to retake the holy city of Jerusalem and continue into other regions of the Middle East, the Crusades lasted until 1291. This period saw several major Crusades, including the First (1096-1099), Second (1147-1149), Third (1189-1191), and Fourth (1202-1204) Crusades, and a number of others leading up to the Ninth Crusade (1271-1272).
Throughout these two centuries, there was a significant impact on the political, economic, and cultural aspects of European and Middle Eastern societies. The Crusaders established Crusader States and brought back knowledge, and goods like silk and sugar, and also, unfortunately, fostered a deep-seated animosity between the two religions. The Third Crusade is notable for figures such as Saladin and Richard the Lionheart, as well as the infamous sack of Constantinople during the Fourth Crusade. The Crusades came to an end when the Crusaders lost their stronghold at Acre in 1291.