Was Europe protected from outside threats under feudalism?

Feudalism in Europe provided a degree of protection from outside threats through a system of local lords and vassals who were responsible for defending their territories. Lords built fortified castles and maintained armed retainers, creating a decentralized defense network. However, this system also made it difficult to mount a unified response to larger external threats, such as invasions, as local allegiances often took precedence over collective action. As a result, while feudalism offered some level of protection, it was not entirely effective against significant external threats.