How did feudal lords in western europe in the 11th century defend their territories?

In the 11th Century, in order to defend their territories, feudal lords in Western Europe raised private armies of knights. In exchange for the knights military service the lords used their most abundant resource, their land. During this time, Western Europe is considered as the battleground of warring nobles vying for power. 

The second , larger puritan colony of massachusetts bay was conceived as a "city upon a hill". but it also struggled with internal turmoil like the salem witch trials and external conflicts like king philip's (metacom's) war.