England · Ruin
King Charles's Castle
King Charles's Castle is a 16th-century polygonal artillery fort on Castle Down, Tresco, built to guard New Grimsby harbour. It survives as a ruined granite blockhouse with low, thick walls and adjacent rectangular earthworks and is managed by English Heritage.
Its prime
1551
Today
Ruin
As it stood in 1551
The shape it held in its prime.
A low, polygonal granite blockhouse set on grassy Castle Down, its front formed as a broad gun battery with five embrasures looking seaward and a large central arched opening; the rear contains rectangular living rooms with doorway and window openings. Walls are of dressed and rubble granite, in places incorporating the underlying rock; surviving wall heights are uneven with collapsed upper sections and scattered fallen blocks. A rectangular earthen bank with a bastion and shallow ditch runs northeast from the building.
Its story
The story of King Charles's Castle.
Built between 1548 and 1551 to protect the Isles of Scilly from French attack, this polygonal granite fort overlooks New Grimsby harbour on Tresco, with a five-gun battery at the front and a hall, kitchen and bedrooms for the garrison behind. The design is unusual for the period, seen elsewhere only in blockhouses along the Thames — and it proved unsatisfactory: the guns could not be angled to fire down into the harbour, and the Star Castle on neighbouring St Mary's eventually became the main fort in the islands.
After the Civil War the Scillies were held by Royalist sympathisers of King Charles I, who gave the castle its current name. When Sir Robert Blake's Parliamentary force landed on Tresco in 1651 it bypassed the fort as it took the island; the Royalist defenders blew up parts of the castle as they left, and some of its stone appears to have gone into the newer Cromwell's Castle by the harbour.
Soldiers were still housed there in 1660, but by the 18th century the castle was described as ruinous. The Crown, through the Duchy of Cornwall, leased the islands to the Godolphin family in 1687 and to Augustus Smith in 1834; in 1922 Arthur Dorrien-Smith agreed to pass the castle into the guardianship of the Ministry of Works. It is now in the care of English Heritage, protected as a scheduled monument and a Grade II* listed building.
Step inside
9 places to explore in 1551.
The record describes 9 distinct spots at King Charles's Castle — including 5 interiors: inside the gun battery (interior), hall and kitchen (rear large room), north bedroom off the hall (interior) and more. Create your own photoreal reconstruction and walk through every one — more scenes means more photos, more angles and more rooms of the immersive experience.
Create History
Recreate King Charles's Castle with AI to explore it.
The artist rebuilds it as it stood in 1551 — a photoreal walk that belongs to you alone. Pay with coins, no subscription needed.
Recreate Castle to Explore →Whose castle
Clans who held King Charles's Castle.
The families that held King Charles's Castle for a decade or more across its history — follow a name to its clan.
Godolphin
Held the Isles of Scilly, with the castle, on lease from the Duchy of Cornwall from 1687 to 1834.
Augustus Smith took the lease of the islands in 1834; in 1922 it passed to Arthur Dorrien-Smith, who put the castle into the guardianship of the Ministry of Works.
