Although many people know that Plymouth once had a castle and that it was built on top of Lambhay Hill in the Barbican, not much else was known about it. Recent research has uncovered the story of the Castle Quadrate as it was known, and the story of the early defences of Plymouth.
The defence to be built was a chain across the entrance to Sutton Pool so that the townspeople could stop enemy ships from entering the harbour. The chain needed strong, defensive buildings at each end called the Barbican Blockhouse and the Chain Tower. Overlooking these buildings they first built a Fort close to the water and later they built a larger castle on the hill overlooking the entrance to Sutton Harbour.
The Origins of Plymouth
We do not know when the first defences were built but an old document mentions that they were built sometime between 1272 and 1307. The first mention of a ‘castle’ was in 1312, but this was probably referring to the smaller Barbican Fort. There are no pictures of the small Fort and only a few pictures that show the later Castle so most of what we know we have pieced together from a few surviving old documents.
Sutton, the place that later became Plymouth, was originally a small fishing village on the shore of a sheltered tidal pool, protected from bad weather by the high ground of Plymouth Hoe. The village grew in size and became rich through trade in French wine, local wool, a plentiful supply of fish and metals from Dartmoor. At this time Sutton was not defended and could be easily attacked by sea, it was close to the coast of France and a long way from any support from the government in London. War with France made Plymouth an easy target for ‘hit and run’ raids so the local landowners and citizens built their own defences so they could control which ships could come into Sutton harbour.
Find out more about the origins of Plymouth 
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Timeline
1211 First mention of ‘Plymouth’ in official records
1307 Chain Boom at Plymouth first mentioned
1312 First mention of a ‘castle’ at Plymouth, probably the Fort
1337 Start of the Hundred Years’ War against the French
1339 Start of raids by the French on Plymouth, town destroyed
1377 Plymouth was attacked and burnt by a French fleet
1377 Castle Quadrate construction started
1400 French raid on Plymouth under James of Bourbon
1403 St Lawrence Day raid on Plymouth, Castle destroyed
1416 Castle Quadrate rebuilt
1439 The town of Plymouth created
1520 Castle Quadrate strengthened by Bishop Veysey
1585 Castle Quadrate extensively rebuilt, Chain Boom removed
1588 Spanish Armada sails past Plymouth
1597 The Hoe Fort built, Castle Quadrate now obsolete
1666 Royal Citadel built, Castle Quadrate demolished
1790 Barbican Blockhouse demolished, West Pier built
See the complete timeline for Plymouth .
The First Defences of Plymouth
The first defences of Sutton Harbour were a strong Blockhouse with a Chain Tower opposite and a 20m long chain boom between them to control access to ships. The gap between the Chain Tower and the eastern shore at Teats Hill was blocked by a low rocky tidal reef called the Cawse.
The chain boom was a heavy iron chain attached to a long and heavy timber. Each end of the chain was attached to a windlass so the chain and timber could be raised to stop ships entering the harbour or it could be lowered to the seabed so ships could sail over the top.
The Blockhouse was built at sea level and its roof was at the same height as the West Pier is now. A small fort was built inland from the Blockhouse to defend the area from attack by sea, this fort was enclosed by high walls and had a single tall round tower where defenders could fire arrows down onto the enemy.
The new defences were tested in 1339 during the first raid by the French on Plymouth, the Barbican Blockhouse and Fort were overrun by the enemy and much of the town was destroyed, showing that stronger defences were needed.
The French again threatened Plymouth in the 1370s so King Edward III ordered that a survey be made of the town defences. In 1377 Plymouth was again attacked and burnt by a French fleet so the town started to build a better defence and the construction of the Castle Quadrate was started.
Find out more about medieval warfare in Plymouth .
The Castle Quadrate
The Castle Quadrate was a typical design of this period with four round towers joined by four tall walls in a rectangular shape. The Castle walls were built of stone and lime mortar, with walkways on the top of the walls and towers for the defenders, with crenelations and loopholes built-in and holes along the parapet walls where the defenders could fire down on the enemy.
The Castle was built on top of the hill that overlooks the Barbican Blockhouse and Chain Boom so that guns on the Castle could fire on enemy ships.
There was another raid by the French in 1400 and again in 1403, this was the famous St Lawrence Day raid on Plymouth by the French under the command of Le Sieur du Chastel where two of the Castle towers and the Cawse were destroyed by the invaders. Two years later the French returned but they were kept away by gunfire. In 1416 Bishop Stafford had the two towers rebuilt and the Cawse repaired, and the Castle was strengthened by Bishop Lacey and Bishop Veysey between 1449 and 1530.
In the 1580s the citizens of Plymouth thought they no longer needed the Chain Boom, so the Barbican Blockhouse was filled with rubble and the Chain Tower was converted into a store. But by 1585 a new threat of an invasion by the Spanish led the citizens to rebuild the Castle Quadrate, but the famous Spanish Armada of 1588 just sailed past Plymouth without stopping.
The Castle Becomes Obsolete
The Hoe Fort and Royal Citadel
The way battles were fought had changed by the 1590s and the Castle was obsolete, so Sir Francis Drake obtained royal funding to build a Fort on Plymouth Hoe and a wall around the town. By the time the Mayflower sailed from Plymouth in 1620, the Castle was no longer being used to defend the harbour.
The Castle was used again briefly during the English Civil War but in 1666 the foundation stone for the new Royal Citadel was laid and at the same time the Castle Quadrate was demolished. The Barbican Blockhouse and Fish House survived until 1790 when they were demolished and buried under the new West Pier.
One of the last structures to survive was one of the oldest, the Barbican Tower which was part of the original Fort was demolished in 1887. But here and there you can still see sections of old wall which may be part of the original Fort, and all that is left of the Castle Quadrate is the entrance to it in Cooksley Court off Castle Street.
The Mayflower Steps
It is thought that the steps used by the Mayflower Pilgrims when they left Plymouth in 1620 were under the Admiral MacBride pub, but this is not true. There are many old maps that show where the steps were on the north side of the old Barbican Blockhouse, now under the modern West Pier and Quay. What was under the pub was something much older, it was the tower that was part of the Fort that originally defended the Barbican and the entrance to Sutton Harbour.
The Castle Site Today
The landscape where the Barbican, Fort and Castle Quadrate were built still survives today under modern buildings. The roads around Lambhay Hill follow the original tracks made when the Castle was first built. The Round House on Lambhay Hill may be on the site of the original Fort gatehouse but the structure is probably a reconstruction. A stairway behind the Round House follows the route of a much older stairway that was part of the original Barbican Fort. The large rock platform that overlooked the Barbican Blockhouse is now part of Lady Astor’s Garden, its walls covered in green foliage.
