The monument comprises the remains of Fort Pitt, an early C19 century fort forming part of the defences for Chatham Dockyard. Although the necessity of defending the hill south of Chatham had been identified in the late C18 century it was only in 1805 that construction began in response to the increased threat of a French invasion during the Napoleonic Wars (1803-1815). The Fort was named after Prime Minister William Pitt who died in 1806. The Fort was also an important military hospital from the early C19 to the early C20. The monument embodies the perceived need in the early C19 century to strengthen the Chatham defences against expected French attack. It is also a physical reminder of the rapidly changing international situation in the early 1800s. While the justification for its construction might have declined following the Battle of Trafalgar in 1805, very large sums continued to be spent on anti-invasion defences in Chatham for at least the next decade, with Fort Pitt exemplifying experimentation in defence given its construction and form. The monument was also a key military hospital of the period with surviving physical remains which illustrate this usage.