Qualla: King Charles's Castle

King Charles's Castle: Introduction

Sat, 23 May 2026 00:00:00 GMT

Photo credit Northerner, CC BY-SA 4.0. King Charles's Castle has a problem with geometry. Built between 1548 and 1551 on the highest point of Castle Down, forty metres above the entrance to New Grimsby harbour, its guns can only fire on enemy ships in the harbour by being angled steeply downward - and downward-angled cannon do not shoot straight. Francis Godolphin, who rented Tresco from the Crown in the late sixteenth century, complained that the fortress 'neither discovereth the whole harbour' and that its design was 'of so weak form as it cannot be defended.' He was correct. By 1594 a much better fort - the eight-pointed Star Castle on St Mary's - had taken over its role. By 1651 the Royalist defenders had blown up part of it themselves. By 1752 the antiquary William Borlase was calling it 'a work of labour and expense, rather than of skill.' Today it is a Grade II* listed ruin maintained by English Heritage, and visitors can walk through walls that survive up to 3.4 metres high.

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Image: Northerner | CC BY-SA 4.0

King Charles's Castle: A French Invasion Scare

Sat, 23 May 2026 00:00:00 GMT

Photo credit Daniel Bagshaw, CC BY-SA 2.5. The castle was built in the reign of the boy-king Edward VI, but the fear that drove it back to his father's time. Henry VIII had built a chain of artillery forts around the south coast of England in the 1530s and 1540s - bold, low, thick-walled batteries designed to fire the new...

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Image: Daniel Bagshaw | CC BY-SA 2.5

King Charles's Castle: The Design Problem

Sat, 23 May 2026 00:00:00 GMT

Photo credit Northerner, CC BY-SA 4.0. The castle is polygonal, built from local granite, with a gun battery at the front and a dining room, kitchen and living quarters behind. The plan is unusual for the period and survives elsewhere only in a few small blockhouses along the River Thames - none of which were exposed ...

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Image: Northerner | CC BY-SA 4.0

King Charles's Castle: The Royalists and the Demolition

Sat, 23 May 2026 00:00:00 GMT

Photo credit William Borlase (1695 – 1772), Public domain. During the English Civil War the Scilly Isles backed Charles I, and after a brief period in Parliamentary hands they rebelled in 1648 to support him. The Royalist garrison on Tresco believed - perhaps optimistically - that the castle on Castle Down was a critical defensive positi...

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Image: William Borlase (1695 – 1772) | Public domain

King Charles's Castle: The Stone Reused

Sat, 23 May 2026 00:00:00 GMT

Photo credit Northerner, CC BY-SA 4.0. Some of the stone from the demolished King Charles's Castle was almost certainly carried downhill and incorporated into the new Cromwell's Castle, which Blake's masons built at sea level over the following year. The exchange feels almost narrative: a Royalist fort blown up by its...

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Image: Northerner | CC BY-SA 4.0

King Charles's Castle: What Remains

Sat, 23 May 2026 00:00:00 GMT

Photo credit Northerner, CC BY-SA 4.0. In 1922 the lease of the castle passed to Arthur Dorrien-Smith of Tresco Abbey, who handed it - along with several other Tresco properties - to the Ministry of Works. In 1954 the site was partially excavated, uncovering coins, pottery and a buckle, and parts of the first floor of...

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Image: Northerner | CC BY-SA 4.0