Isles of Scilly History Overview

The Isles of Scilly (/ˈsɪli/; Cornish: Syllan, Ynysek Syllan, or Ynysow Syllan) is an archipelago off the southwestern tip of Cornwall. One of the islands, St Agnes, 

The total population of the islands at the 2011 United Kingdom census was 2,203.

 Scilly forms part of the Duchy of Cornwall, and some services are combined with those of Cornwall.

 However, since 1890, the islands have had a separate local authority. 

Since the passing of the Isles of Scilly Order 1930, this authority has had the status of a county council and today is known as the Council of the Isles of Scilly.


Historically, the Isles of Scilly were known in Latin as Insulae Sillinae, Silina or Siluruni, corresponding to Greek forms Σίλυρες and Σύρινες.

 In the Late Middle Ages they were known to European navigators as Sorlingas (Spanish, Portuguese) or Sorlingues (French). 

In the Cornish language, the Isles of Scilly is Syllan.

The etymology is unknown.

 Some authors suggest the Latin Sillinae is derived or related to solis insulae, "the Isles of the Sun".


Early history

Projected coastline of the Isles of Scilly in 3,000 BCE, as supported by Barnett et al.

The islands may correspond to the Cassiterides ('Tin Isles') believed by some to have been visited by the Phoenicians, and mentioned by the Greeks. 

However, there is no evidence of substantial tin mining activity on the islands.

The isles were off the coast of the Brittonic Celtic kingdom of Dumnonia and later its offshoot, Kernow (Cornwall).

It is likely that until relatively recent times the islands were much larger and perhaps joined into one island named Ennor. Rising sea levels flooded the central plain around 400–500 AD, forming the current 55 islands and islets, if an island is defined as "land surrounded by water at high tide and supporting land vegetation".

 The word Ennor is a contraction of the Old Cornish 

En Noer (Doer, mutated to Noer), meaning 'the land' or the 'great island'.

Evidence for the older large island includes:

Offshore, midway between Land's End and the Isles of Scilly, is the supposed location of the mythical lost land of Lyonesse, referred to in Arthurian literature, of which Tristan is said to have been a prince. 

This may be a folk memory of inundated lands, but this legend is also common among the Brythonic peoples; the legend of Ys is a parallel and cognate legend in Brittany as is that of Cantre'r Gwaelod in Wales.

Scilly has been identified as the place of exile of two heretical 4th century bishops, Instantius and Tiberianus, who were followers of Priscillian.

Norse and Norman period

Olaf Tryggvason, who visited the islands in 986. It is said an encounter with a cleric there led him to Christianise Norway.

At the time of King Cnut, the Isles of Scilly fell outside England's rule, as did Cornwall and Wales.

Scilly was one of the Hundreds of Cornwall (formerly known as Cornish Shires) in the early 19th century.

At the turn of the 14th century, the Abbot and convent of Tavistock Abbey petitioned the king,

stat[ing] that they hold certain isles in the sea between Cornwall and Ireland, of which the largest is called Scilly, to which ships come passing between France, Normandy, Spain, Bayonne, Gascony, Scotland, Ireland, Wales and Cornwall: and, because they feel that in the event of a war breaking out between the kings of England and France, or between any of the other places mentioned, they would not have enough power to do justice to these sailors, they ask that they might exchange these islands for lands in Devon, saving the churches on the islands appropriated to them.

William le Poer, coroner of Scilly, is recorded in 1305 as being worried about the extent of wrecking in the islands, and sending a petition to the King. 

The names provide a wide variety of origins, e.g. Robert and Henry Sage (English), Richard de Tregenestre (Cornish), Ace de Veldre (French), Davy Gogch (possibly Welsh, or Cornish), and Adam le Fuiz Yaldicz (possibly Spanish).

It is not known at what point the islanders stopped speaking the Cornish language, but the language seems to have gone into decline in Cornwall beginning in the Late Middle Ages; it was still dominant between the islands and Bodmin at the time of the Reformation, but it suffered an accelerated decline thereafter. 

The islands appear to have lost the old Celtic language before parts of Penwith on the mainland, in contrast to the history of Irish or Scottish Gaelic.

During the English Civil War, the Parliamentarians captured the isles, only to see their garrison mutiny and return the isles to the Royalists.

 By 1651 the Royalist governor, Sir John Grenville, was using the islands as a base for privateering raids on Commonwealth and Dutch shipping. 

The Dutch admiral Maarten Tromp sailed to the isles and on arriving on 30 May 1651 demanded compensation. In the absence of compensation or a satisfactory reply, he declared war on England in June.

 It was during this period that the disputed Three Hundred and Thirty Five Years' War started between the isles and the Netherlands.

In June 1651, Admiral Robert Blake recaptured the isles for the Parliamentarians. 

Blake's initial attack on Old Grimsby failed, but the next attacks succeeded in taking Tresco and Bryher.

 Blake placed a battery on Tresco to fire on St Mary's, but one of the guns exploded, killing its crew and injuring Blake. 

A second battery proved more successful. Subsequently, Grenville and Blake negotiated terms that permitted the Royalists to surrender honourably. 

The Parliamentary forces then set to fortifying the islands. They built Cromwell's Castle—a gun platform on the west side of Tresco—using materials scavenged from an earlier gun platform further up the hill.

 Although this poorly sited earlier platform dated back to the 1550s, it is now referred to as King Charles's Castle.

The Isles of Scilly served as a place of exile during the English Civil War. Among those exiled there was Unitarian Jon Biddle.

During the night of 22 October 1707, the isles were the scene of one of the worst maritime disasters in British history, when out of a fleet of 21 Royal Navy ships headed from Gibraltar to Portsmouth, six were driven onto the cliffs. 

Four of the ships sank or capsized, with at least 1,450 dead, including the commanding admiral Sir Cloudesley Shovell.

There is evidence of inundation by the tsunami caused by the 1755 Lisbon earthquake.


The Isles of Scilly form an archipelago of five inhabited islands (six if Gugh is counted separately from St Agnes) and numerous other small rocky islets (around 140 in total) lying 45 kilometres (24 12 nautical miles) off Land's End.[29]

The islands' position produces a place of great contrast; the ameliorating effect of the sea, greatly influenced by the North Atlantic Current, means they rarely have frost or snow, which allows local farmers to grow flowers well ahead of those in mainland Britain. 

The chief agricultural product is cut flowers, mostly daffodils. 

Exposure to Atlantic winds also means that spectacular winter gales lash the islands from time to time.

This is reflected in the landscape, most clearly seen on Tresco where the lush Abbey Gardens on the sheltered southern end of the island contrast with the low heather and bare rock sculpted by the wind on the exposed northern end.

In 1975 the islands were designated as an Area of Outstanding Natural Beauty. 

The designation covers the entire archipelago, including the uninhabited islands and rocks, and is the smallest such area in the UK. 

The islands of Annet and Samson have large terneries and the islands are well populated by seals. 

The Isles of Scilly are the only British haunt of the lesser white-toothed shrew (Crocidura suaveolens), where it is known locally as a "teak" or "teke".

The islands are famous among birdwatchers for the large variety of rare and migratory birds that visit the islands. The peak time of year for sightings is generally in the autumn.

Tidal influx

The tidal range at the Isles of Scilly is high for an open sea location; the maximum for St Mary's is 5.99 m (19 ft 8 in). 

Additionally, the inter-island waters are mostly shallow, which at spring tides allows for dry land walking between several of the islands. 

Many of the northern islands can be reached from Tresco, including Bryher, Samson and St Martin's (requires very low tides). 

From St Martin's White Island, Little Ganilly and Great Arthur are reachable. 

Although the sound between St Mary's and Tresco, The Road, is fairly shallow, it never becomes totally dry, but according to some sources it should be possible to wade at extreme low tides. 

Around St Mary's several minor islands become accessible, including Taylor's Island on the west coast and Tolls Island on the east coast.

 From Saint Agnes, Gugh becomes accessible at each low tide, via a tombolo.


The Isles of Scilly have a temperate oceanic climate (Köppen climate classification: Cfb), which borders a humid subtropical climate (Cf) under the Trewartha climate classification.

  The average annual temperature is 12.0 °C (53.6 °F), the warmest place in the British Isles.

   Winters are, by far, the warmest in the UK due to the moderating effects of the North Atlantic Drift of the Gulf Stream.

   Despite being on exactly the same latitude as Winnipeg in Canada, snow and frost are extremely rare.

 The maximum snowfall was 23 cm (9 in) on 12 January 1987.

 Summer heat is moderated by the Atlantic Ocean and summer temperatures are not as warm as on the mainland. However, the Isles are one of the sunniest areas in the southwest with an average of seven hours per day in May. 

The lowest temperature ever recorded was −7.2 °C (19.0 °F) and the highest was 27.8 °C (82.0 °F).

The isles have never recorded a temperature below freezing in the months from May to November inclusive. 

Precipitation (the overwhelming majority of which is rain) averages about 35 in (890 mm) per year. 

The wettest months are from October to January, while April and May are the driest months.


All the islands of Scilly are all composed of granite rock of Early Permian age, an exposed part of the Cornubian batholith.

 The Irish Sea Glacier terminated just to the north of the Isles of Scilly during the last ice age.

Ancient monuments and historic buildings

Historic sites on the Isles of Scilly include:

Bant's Carn, a Bronze Age entrance grave

Halangy Down Ancient Village

Porth Hellick Down Burial Chamber

Innisidgen Lower and Upper Burial Chambers

The Old Blockhouse

King Charles's Castle

Harry's Walls, an unfinished artillery fort

Garrison Tower

Cromwell's Castle