Defense: Forts provided a defensible location for European settlers and soldiers in a new and often hostile environment. They could be used to protect against attacks from Native American tribes, rival European powers, or other threats.
Trade: Forts could also serve as trading posts, where Europeans could interact with Native Americans and exchange goods.
Exploration: Forts could be used as bases for exploration of the surrounding area.
Control: Forts could help Europeans to maintain control over their territory and assert their authority over Native American tribes.
Settlement: Forts could act as hubs for new settlements, providing a secure location for people to live and farm.
Religious Conversion: Many European forts were also mission sites, meant to convert native peoples to Christianity
The specific purposes of a fort could vary depending on the time period and the location. For example, some forts were primarily used for defense, while others were more focused on trade or exploration.