Historical context behind feudalism?

"Feudalism was a combination of legal and military customs in medieval Europe that flourished between the 9th and 15th centuries. Broadly defined, it was a way of structuring society around relationships derived from the holding of land in exchange for service or labour."

the dominant social system in medieval Europe, in which the nobility held lands from the Crown in exchange for military service, and vassals were in turn tenants of the nobles, while the peasants were obliged to live on their lord's land and give him homage, labor, and a share of the produce, notionally in exchange for military protection.

The correct answer is the hindu kush mountains.