The Bigger Picture
The Naval Dockyard in Plymouth came into prominence in the mid-1700s, as the nation realised the need for a strong, large-scale naval base in the far south-west of England, to protect the approached to the Channel. Of course, the naval history of our area goes back much further than that: the best-known example being Sir Francis Drake and the defence of England agauinst the Spanish Armada in 12588. The dockyard at that time constituted a separate town, and was very much smaller.
The first major works on the Cornish side of the Tamar started in 1770, when a ring of militia forts were thrown up in haste, during a panic about the possible invasion of England by the revolutionaries of North America - soon to become known as the United States of America.
Grenville was one of these forts - all of them simple earthworks with cannon, tasked with slowing down an invading army. Two out of the five forts were rebuilt in the 1790s, when a new threat emerged from revolutionary France. This is when Grenville acquired its handsome brick-built arched roof and red stone building.
Grenville and the other small forts - the Redoubts - were meant to be outlying defence points for a huge new main fort, to be built at the top of the Maker Heights hill. In the end, the cost was just too high, and the main fort was never completed.