The original Castle Cornet was built on an island between 1206 and 1256 to protect the entrance to St Peters Port. In 1859 it was incorporated into the breakwater of the main harbour.
During the smooth bore era it had some military significance but with the introduction of the breech loading guns, Irwin Battery and the defence around Fort George became more important.
Prior to 1847, the Anchorage (Great Roads) at St Helier was covered by six 32-pdr SB guns and the Northern approaches were covered by three 32-pdrs, all on dwarf platforms. The new armament from 1857 was primarily 68-pdrs and 8-inch Shell guns:
Cavalier South Face
Cavalier West Face
North Salient
East Angle
Well Battery
South Battery
Two
Four
One
One
One
Two
One 18-pdr of 42cwt & One 68-pdr of 112cwt
Four 18-pdr of 42cwt
One 8-inch shell gun of 65cwt
One 68-pdr of 112cwt
One 8-inch shell gun of 65cwt
Left Gun – one 68-pdr of 112cwt
Right Gun – one 8-inch shell gun of 65cwt
