Complex sentence: To guard against such attacks, the 84th Regiment was garrisoned at four forts around the Bay of Fundy, such as Fort Howe Fort Frederick was destroyed and rebuilt at Fort Howe.
Split into simpler sentences: To guard against such attacks, the 84th Regiment was garrisoned at various forts around the Bay of Fundy. One such as Fort Howe Fort Frederick was destroyed and rebuilt at Fort Howe.