The strategic position of the Islands was key in the defence of Britain in the 16th century. The Islands were one of Britain’s main ports at the time. The position of Scilly, south west of mainland Britain by about 28 miles, was a position that the navy had to hold if they were to protect Britain from any other invasion.

Harry’s Walls

The first attempt at protecting Scilly’s harbour was Harry’s Walls, named after King Henry VIII and built by Sir John Kiligrew in 1551 and was widely dubbed as a gastronomic waste of the £6000 of Royal funds, and the castle was to have very little effect as it was never completed. Kiligrew, who already was responsible for the successful Pendenis Castle in Falmouth, had chosen a poor site for this particular addition to the chapter in Scilly’s defences.

The Castle was too far away from the harbour to have any real benefit and also was out of range of the Eastern and Western approaches to the harbour.

A major disadvantage of the Castle’s position was that it only protected one half of the town, and the Porth Cressa side, which would later be protected by Star Castle and its Garrison, remained a weakness in the shell of fortification needed to encapsulate Scilly.

King Charles’s Castle

Tresco also had an important harbour, so defences were made there as well. Kiligrew and his son again had the task of picking a site for King Charles’ castle, built in 1550, (before Harry’s walls).

The site was poor. It did overlook the harbour and did cover a wide area but it was built on top of a hill and this did not help the range of the cannons as only one entrance to the harbour was covered. It also proved a difficult task to get the cannons pointing down at the right angle, and as the castle was built on a steep hill, as long as ships stayed close to the shore, the cannons would overshoot every time.

Though not tested in wartime, “[It] can make no good shot so steep downwards,” said Francis Godolphin. It seems that the main factor that Kiligrew took into consideration when deciding the site for a new castle was the height of the land on which the castle was built.

Unfortunately, Kiligrew did not take other important features into account, such as geometry of the cannon fire which made Harry’s Walls and King Charles’ Castle so unsuccessful. In contrast, one of the great success stories of fortifications in Scilly was Cromwell’s castle, built in 1651 as a replacement for King Charles.

Cromwell’s Castle

It became clear that Tresco needed to be defended, as the Dutch also posed a threat to the security of Scilly. The advantage that invading forces would find in Tresco harbour was that It was very sheltered (by Bryher to the west and Tresco to the east) and therefore an extremely good place to moor invading ships. With the harbour covered, ships would be forced to moor in other, more exposed areas.

Cromwell’s Castle was built using some of the stones from the earlier King Charles’ Castle (probably the most important and useful role of Charles’s castle!).

Cromwell’s castle protected Tresco harbour from the north and from the south and as it was closer to the sea, canon fire would have been much more effective than King Charles.

Star Castle

Star Castle is the centrepiece of an impressive fortification system around the west side of St Mary’s known as the Garrison. It comprises of an outer wall all the way around the outcrop, protecting the town and the castle, at regular intervals there are strategically placed gun batteries around the outer wall, protecting the castle from all angles. The Idea was that the locals could seek protection in this garrison if an attack commenced.

Spanish Armada

The Castle was built as a direct consequence of the Spanish Armada of 1588. Fearing another invasion from the Spaniards, Queen Elizabeth I was advised to build a fortification in Scilly as a lookout for any intruder ships, threatening Britain, especially from another attack from the Spaniards. It was believed that Spain was hatching another plot to overthrow the British Monarchy and religion, for its part in helping the revolt of Protestants in the Netherlands (a Spanish territory at the time) and it was believed that if they were to regain the Netherlands they would first have to defeat Britain.

The British government were advised that the Spanish were to take Scilly in order to use it as a stepping stone and supply base from which to launch an attack on Britain. There was no doubt that an invasion of Britain would be more likely to be successful if Spain had Scilly as a base. This is why Star Castle was built, and why it was so important as a British navy port.

In the 16th century the Isles of Scilly were one of the main and most important ports in Britain as it boasted sheltered and deep waters and it was a vital position to the navy and defences of Britain and the government were willing to go to great lengths to ensure that the Isles of Scilly remained under control of the British forces.

In 1574 Philip of Spain set out orders for Scilly to be seized, but the fleet that were to carry out the task were struck by the plague and the plan was abandoned. This was one of the determining factors, comprising the decision to build Star Castle. Even after the failed Spanish Armada it was still reckoned that Spain was the greatest military force on the planet and further invasions were feared.

World War II

The strategic position of Scilly has been recognised as recently as the WW II, when Scilly was to become a naval base for the new dreadnoughts until Plymouth was favoured because of her deeper waters.

Star Castle: The Star-Shaped Castle

Star Castle was so called because its walls took the shape of an eight pointed star.

The eight points are not just decorative or a showpiece for the architects work, they also had a practical use, which was that if invaders got too close to the castle, soldiers could fire easily at the invaders but it became difficult for invaders to fire back at the small openings in the wall that was likely to be at an awkward angle.

The star shape was better than a conventional round shape, because if one wall of the castle was hit by a cannon, the shape would keep its structural stability as it would be likely that only one side of the castle would be damaged.

The Hoe

Star Castle was originally built in 1593, under the direction of Francis Godolphin (the man who rented the land from the Duchy of Cornwall) and was situated on one of the highest parts of St Mary’s, The Hoe.

The main advantage that this had over previous sites such as Harry’s Walls or Ennor Castle in Old Town was that The Hoe was a small outcrop joined to the main part of the island by a thin strip of land, on which lay the densely populated Hugh Town.

As well as overlooking the important harbour The Hoe also overlooked the Pool which was an area where trading vessels and invading forces would try and lay anchor. The Hoe had a very wide angle of cannon fire as it was surrounded by water and the castle itself was on top of the hill so that nothing would obstruct the firing of cannons.

Unlike King Charles’ Castle, the hill meant the cannon ball had to travel further.

Abraham Tovey

In 1740, Master Gunner Abraham Tovey transformed the Garrison surrounding Star Castle, as he built walls of stone and gun batteries in a circular shape following the coast line of The Hoe. This acted as extra security and completed the fortifications with an important addition, as this new outer wall ensured that enemy ships could be fired upon as they approached the Garrison and not only when they were moored in the Pool.

This new Garrison replaced a less impressive system of earthworks and the rectification remain impressive to this day with cannons. ranging from 800 pounds to 4000 pounds still prominent on four of the ten batteries positioned around the walls of the Garrison.

1740: New Defences

The main batteries are the Woolpack battery (facing South West), the Morning Point battery (facing South East and covering Porth Cressa, another strategic stronghold), the Steval battery (facing West) and King Charles Battery (facing North and protecting the harbour).

As well as Star Castle, inside the walls of the Garrison there is a powder room . This powder room supplied gunpowder for the cannons. of Star Castle and the Garrison, and as all of the batteries were connected by a well maintained road which meant it was easy to transport the powder, this shows that the advanced planning and small details were considered carefully.

There is a mechanism on King Charles battery which consisted of a 2000-pound cannon on a turntable, which would have made the cannon much easier to manoeuvre.

The gate to the Garrison had a Port Cullis and huge doors and all the walls of the Garrison were tall and steep making the Garrison virtually impenetrable. Gateway Markings

The gateway to the Garrison still bears the initials A.T. for Abraham Tovey, G.R. for George Regina, the monarch in 1740, F.G. for Francis Godolphin (third of four) the lease holder for the islands at the time, and the date 1742 - the date of completion of the Garrison walls.

Never Used

Though the fortifications became more advanced as foresight and technology improved, the defences were never tested.

Building of Star Castle itself may have acted as a deterrent from a second attack from Spain.