There is evidence of settlement, pottery production, agriculture and trade in the area by the beginning of the 5th-century BC.
The earliest remnants of human activity are two sections of a 33ft-long log boat, which was recovered just off Brownsea Island by a dredger in 1964. Carbon-dating revealed that it had been preserved by the marine silts for almost three thousand years. It can now be seen in Poole Museum.
The Romans later settled small communities around Poole Harbour, which developed into larger villages and ports under the Anglo-Saxons. In the 9th-century AD, Viking raiding parties attacked the area until King Alfred's naval fleet drove the Danish ships away in 876.
Medieval Brownsea Island and Christianity
By the late 9th-century a chapel belonging to Cerne Abbey in Dorset stood on the island. A hermit would probably have lived here, administering to the spiritual welfare of seamen.
The Domesday Book of 1086 makes no reference to Brownsea Island, which suggests that there was little of value on the island after the Norman Conquest. Records show that over the next few hundred years however, the monks of Cerne fiercely guarded their right to keep any items washed ashore from shipwrecks.
Henry VIII and military defence
Following the Dissolution of the Monasteries in the 1530s, control of Brownsea Island passed from Cerne Abbey to Henry VIII. The King recognised the strategic importance of the island for guarding the entrance to the thriving port of Poole. The first Brownsea Castle was one of a string of similar 'block' forts designed to defend the south coast of England against invasion from Europe.
A hideout for pirates
By 1576, Brownsea Castle had fallen into ruin and Queen Elizabeth I granted it to one of her court favourites, Christopher Hatton. He promoted Sir Francis Drake's voyage round the world and later became Lord Chancellor.
At this time piracy was rife and captains of the castle were reputed to give protection to some of the era’s leading pirates in return for a share of their booty.
Civil War and the Restoration
During the English Civil War, 1642-51, Poole sided with Parliament and garrisoned a strongly fortified Brownsea Castle throughout. By the time of the Restoration in 1660, Brownsea was owned by Robert Clayton who later became Lord Mayor of London and was one of the MPs who invited William of Orange to take the throne from James II in 1688.
A gentleman's estate
In 1726 Brownsea was bought for £300 by an eccentric and controversial individual, William Benson. He was sometimes known as 'Mad' Benson and is said to have dabbled in black magic.
Benson dismantled the derelict fortifications and rebuilt the castle as a residence. He planted many kinds of trees, and preserved specimens of hundreds of rare plants on the island.
The pattern of improvement to Brownsea continued when Sir Humphrey Sturt of More, a local MP, took over the island. He added wings to the castle, raised it to four storeys, and laid out gardens complete with hot houses.
Grand industrial plans
In the mid-19th century, Brownsea was bought by an ex-Indian army officer, Colonel William Petrie Waugh and his wife Mary. They thought they had discovered the existence of high quality china clay, a key ingredient for porcelain manufacture.
Expecting to make their fortune, they constructed a large three-storey pottery on the south shore, complete with engines, a brickworks and a horse-drawn tram to bring clay from the north of the island.
For the workers, the Colonel constructed a model village called Maryland, after his wife and the neo-Gothic church of St Mary the Virgin. The Branksea Clay & Pottery Company expanded to employ more than 200 people, many of whom rowed over from Studland every day.
The castle received an elaborate makeover, with a new Tudor-style facade, a gatehouse with clocktower and a pier with castellated watchtowers. Plus, a brick wall was built across St Andrew's Bay to reclaim a large parcel of land.
Sadly, the Brownsea clay proved unsuitable for making fine china, and the production of pipes and terracotta chimney pots was not profitable enough to finance the initiative. After only five years of the Waugh's developments, they were forced to claim bankruptcy and emigrated to Spain. Brownsea Island was offered up for auction.
Agriculture and art
By the 1870s Brownsea Island was sold to the Hon George Cavendish-Bentinck MP. He concentrated on improving agriculture on the island, introducing Pedigree Guernsey and Jersey cows, along with arable crops like maize, barley and oats.
He was also a passionate art-collector and filled Brownsea Castle with a spectacular array of Italian Renaissance sculpture, some of which still decorate the church and quay buildings.
When Cavendish-Bentinck died in 1891, the island was bought by Major Kenneth Balfour, another MP. Five years later the castle caught fire. There was no fire engine on Brownsea and, despite the human bucket chain formed by the islanders, the building was gutted. Undaunted, Balfour rebuilt the castle complete with modern fire hydrants. In 1901 he put it back on the market.
In 1901 the well-connected van Raalte family bought Brownsea as their country retreat. The island entered a period of unparalleled prosperity and grandeur. The castle was filled with their splendid collection of musical instruments, which included an electric piano that played Gilbert and Sullivan pieces.
The family's steam launch, the Blunderbuss, brought over wealthy and titled guests from various European royal families. They would enjoy elegant summer house-parties, a new golf course and shoot game in the woods.
Marconi, a favourite guest
One of the more unusual visitors was Guglielmo Marconi, who for many years conducted his experiments with wireless telegraphy at the Haven Hotel opposite Brownsea. He was a particular favourite of the van Raalte's children, to whom he gave a wireless set.
Ordinary life on the island
During the van Raalte's ownership, Brownsea was largely self-supporting, with a kitchen garden and a dairy herd. Many of those who came to work at the pottery factory in the 1850s had stayed on after it closed, farming and working for the castle's owners.
In the 1920s, daffodils were harvested on the main plateau and sold at Covent Garden. All this was done under the watchful eye of estate manager, Tresco Brown, who rode across the island on his boneshaker bicycle.
The community was a small but tight one, in which music and the island band was very important. So important, in fact, that incomers were only allowed to work on Brownsea if they could prove they could play an instrument.
Those who were brought up on Brownsea in the early years of the 20th-century remember it as an idyllic time. But the idyll was to be short-lived. Of the 30 Brownsea islanders who went away to the Great War in 1914, only six returned.
People leave and wildlife flourishes
In 1927, Brownsea Island was sold at auction to Mrs Mary Bonham-Christie for £125,000. She moved into what had been the agent's house on the quay and lived a very reclusive life.
Opposed to blood sports and any other exploitation of animals, she banned fishing and allowed the farm animals to roam wild. The estate, dairy, orchards and daffodil fields were abandoned, and the island gradually reverted to natural heath and woodland.
Most of the redundant estate workers made a sad return to the mainland and with rapid urbanisation of England's south coast, Brownsea became an increasingly important wildlife sanctuary.
A Second World War refuge
In 1940, Brownsea provided a brief haven for exhausted Dutch and Belgian refugees. They had taken to small boats to escape the Nazi invasion of the Low Countries and had been shepherded along the south coast into Poole harbour by the Royal Navy.
Flares were also lit on the western end of the island to mislead German bombers seeking out the harbours of Poole and Bournemouth. As a result, the estate cottages at Maryland, which had mostly been lying empty since 1927, were further damaged and then demolished.
Threat of development - Brownsea is saved
Mrs Bonham-Christie died at the age of 98 in 1961. Her family was obliged to put the island on the market to meet death duties.
When rumours of plans for a marina or luxury housing on Brownsea began to circulate, the Brownsea Island Appeal Committee was formed by a group of concerned local people, with the aim of protecting the island in its unspoilt state.
After the Treasury had accepted the island in lieu of death duties, the National Trust agreed to take over responsibility for it, provided that an endowment of £100,000 was raised.
A nationwide campaign was launched to save the island, and sums large and small came in from local businesses and individuals, charitable trusts and Scouts organisations.
The John Lewis Partnership was a particularly generous donor. They repaired Brownsea Castle and have rented it from the Trust as a hotel for its employees ever since.
The grand public opening
Through the severe winter of 1962-3, the new National Trust Head Warden, his assistant and numerous volunteers worked hard to prepare the island for visitors. Tracks were cleared through rampant rhododendrons and firebreaks cut to prevent repetition of the disastrous fire of 1934.
On 15 May 1963, Jack Battrick wrote in this diary, 'A sultry, but brilliant summer's day found us celebrating our grand overture.' Among the audience at the formal opening ceremony were two of those who had taken part in the first Scout camp 55 years before.