Although a fort from the period of initial European settlement was already in existence the true start of the establishment of the St George's Fortified System was arguably the construction of Fort George from 1706 until 1710. Over the course of the eighteenth century the defence system around St George's gradually evolved on the ridges of the hills that enclose St. George's and its natural harbour like a giant amphitheatre. In its heydays the system consisted of eight forts, designed to mitigate internal Amerindian attacks and slave uprisings, as well as external European rival invasions. At the time of their establishment, each fort progressively incorporated the latest design concepts to facilitate advancing technological achievements of the period, showing today the development of French .and British military engineering adjusted to Grenadian circumstances.
The three major forts of the system have been preserved to the present day. Fort George is associated with all the periods of Grenada's history up to its contemporary period, as the execution of Prime Minister Maurice Bishop in October 1983 was carried out at Fort George. The fort currently houses the Police Headquarters and Police Training School. Fort Frederick is restored and is open to the public. Fort Matthew was converted into a lunatic asylum to serve the entire Windward Island in 1880 and was abandoned in 1987 when a new asylum at Mt. Gay was opened. It is currently in a bad state of repair. The other military structures have either disappeared or fallen to ruins.