What did the Barons have to do in exchange for the land they were granted?

In exchange for the land granted to them, the Barons were typically required to provide military service to the king, which included raising troops and maintaining a certain number of knights. Additionally, they had to pay homage to the king, which involved pledging loyalty and fulfilling various feudal obligations such as taxes and support for the king's endeavors. This system was part of the broader feudal hierarchy that structured medieval society.