The fort guarded Mobile and its citizens for almost 100 years, from 1723-1820. The fort had been built by the French to defend against British or Spanish attack on the strategic location of Mobile and its Bay as a port to the Gulf of Mexico, on the easternmost part of the French Louisiana colony. The strategic importance of Mobile and its fort was significant: the fort protected access into the strategic region between the Mississippi River and the Atlantic colonies along the Alabama River and Tombigbee River.