The original works at this site were built in 1546 when it was know as Essex Castle. With the building of the harbour at St Anne’s in 1840, there was a need to defend this harbour of refuge from land attack. The original Essex Castle was largely built over for the new Essex Barracks. (TNA WO 78/2770 Dated 1869). These barracks were defensible with a gatehouse and loop holed walls to allow musketry fire.