WINDSOR.- From the title deed of Buckingham Palace to George III's reflections on the loss of America, the Royal Archives contains an unparalleled collection of documents that capture key moments in the history of the British Monarchy. To mark the centenary of the establishment of a permanent home for the Archives in the Round Tower at Windsor Castle, more than 100 documents from the private archive of the Royal Family are published in a new book, Treasures from the Royal Archives, and 25 of the most fascinating items go on display at the Castle from Saturday, 17 May, many for the first time.

In the exhibition, and among the documents on display for the first time, is the title deed for Buckingham Palace. Dated 20 April 1763 and bearing George III's wax seal, it records the purchase of Buckingham House from Sir Charles Sheffield for the sum of £28,000 (over £2,000,000 today). Named after its previous owner, the sixth Duke of Buckingham, the property was bought by the King for his wife, Queen Charlotte, to accommodate their growing family – they had 15 children.

Often remembered as the monarch who lost the American colonies, George III wrote his personal reflections on Britain's relationship with America following the end of the War of Independence in 1783. The Crown and Government received much public criticism for the manner in which the conflict was handled; however the King's essay takes a surprisingly sanguine approach to the defeat. Opening with the words 'America is lost!', it assesses the impact of the independence of America on the wealth of Britain, concluding with the King's hope that 'we shall reap more advantages from their trade as friends than ever we could derive from them as Colonies…'.

The Royal Archives includes thousands of papers relating to the exiled Stuarts. The documents not only reflect the continuing Jacobite efforts to reclaim the throne for the Stuart royal line, but also shed light on the private lives of the Stuart family. A letter written in 1728 by the seven-year-old Bonnie Prince Charlie will go on display in the exhibition for the first time. Written to his father, Prince James Francis Edward Stuart, from Palazzo Muti, the Stuart residence in Rome, it appears to be the young boy's response to a reprimand for upsetting his mother. The Prince writes, 'Dear Papa, I thank you mightily for your kind letter. I shall strive to obey you in all things. I will be very Dutifull to Mamma, and not jump too near her…'.

Also on display for the first time is Major John Chard's account of the Defence of Rorke's Drift. Written at the request of Queen Victoria, it describes with the help of sketches and plans the unlikely victory of British troops on the night of 22 January 1879, when Chard's men successfully defended the field station at Rorke's Drift from Zulu attack, despite being heavily outnumbered. Chard recalls the moment when they 'saw them, apparently 500 or 600 in number, come around the hill to our south and advance at a run' and describes how 'many of the men behaved with great gallantry'. Upon his return to England, Chard, along with Lieutenant Bromhead and other officers, was summoned to Balmoral to recount the battle to the Queen, who had followed the progress of the Anglo-Zulu War with great interest.

A report prepared for King George V by the Prime Minister, James Ramsay MacDonald, records a turning point in British politics – the first sitting of the House of Commons under the first Labour Government on 13 February 1924. Describing the occasion as 'unique and historical in the annals of the British parliament', MacDonald concludes that, although it was a 'difficult and trying ordeal', 'on the whole it was a very encouraging start'. The report is just one of many examples of correspondence, both formal and private, between monarchs and political leaders held in the Royal Archives, including letters from the President of the United States, Abraham Lincoln, and British Prime Ministers Winston Churchill and Benjamin Disraeli.

Exhibition curator Lauren Porter of Royal Collection Trust said, 'The 100th anniversary of the foundation of the Royal Archives at Windsor Castle provides a wonderful opportunity to explore and exhibit some of the greatest treasures in the collection of documents. The wide variety of material held in the Royal Archives – from private correspondence and diaries to official papers – provides a fascinating insight into the history of the British Monarchy, often from a very personal perspective.'