What did the income of the Lords and Knights depend on?

The king kept some land for himself and gave fiefs (FEEFS), or land grants, to his most important lords, who became his vassals. In return, each lord promised to supply the king with knights in times of war. A lord then enlisted lesser lords and knights as his vassals.

Explanation:

the answer to your question is,

old stone age.

-mabel < 3

answer; allows decision to stand;