What was the purpose of a fort for?

The primary purpose of a fort was to serve as a defensive structure to protect against military attacks and invasions. Forts were strategically built to provide a stronghold for troops, secure valuable territory, and control trade routes. They often housed armaments, supplies, and soldiers, facilitating military operations and offering a refuge for civilians during conflicts. Additionally, forts played a role in asserting territorial claims and establishing a presence in contested regions.