Royal documents including a letter from the young Bonnie Prince Charlie to his father, Prince James, and Queen Elizabeth I's household account book go on display for the first time at Windsor Castle on Saturday.

In 1914, during the reign of George V, the archives were given a permanent home in the famous Round Tower at Windsor Castle, but only now, to mark the centenary, have documents been put on public display there.

The archives are believed to contain more than two million documents but only a handful of selected historians and researchers are usually allowed to view items from the collection.

While the contents of some documents have been made public before, many are being displayed in their original form for the first time. Others are completely new to historians.

Maj John Chard's account of the Battle of Rorke's Drift, 22 January 1879

Image copyright Royal Archive

A vivid description given to Queen Victoria of the battle that inspired the film Zulu starring Michael Caine. Despite being vastly outnumbered by almost 25-1, British forces successfully defended a small field station in the face of a full-blown Zulu attack lasting more than 10 hours. "We saw them, apparently 500 or 600 in number, come around the hill to our south and advance at a run against our wall," Maj Chard writes. Accompanying illustrations show his skill in draughtsmanship.

Letter from Bonnie Prince Charlie to his father, 4 May 1728

Image copyright Royal Archives

The 64-word letter from seven-year-old Bonnie Prince Charlie reassures his father that he is being well-behaved during the Stuart family's exile in Rome. The line about being "much obliged to the Cardinal for his animals" is probably a reference to a cardinal who would have visited the family and brought gifts to the young prince.

According to exhibition curator Lauren Porter, the letter, written with care in a child's script and including signs of corrections, reinforces the view that the young prince was an exuberant and boisterous child.

Title deeds for Buckingham Palace, 20 April 1763

Image copyright Royal Archives

This document outlines the purchase by King George III of Buckingham House from Sir Charles Sheffield. The sum of £28,000 changed hands (about £2m in today's money), to be paid over two years in four instalments. The vendor would have been given an identical copy of the document, with a rough torn edge to prove that it was taken from the same section of parchment thus preventing forgery.

Household accounts of Princess Elizabeth, 1551-1552

Image copyright Royal Archives

The future Queen Elizabeth I checked her household accounts at Hatfield House. Payments were made "to John Baptiste for lute strings for her grace, Thomas Brierly for flowers in the month of July and Garrett Johnson for 14 pairs of shoes in the month of September". Elizabeth's signature is at the bottom of each page.

Prince Albert describes The Battle of Jutland, 31 May 1916

Image copyright Royal Archive

The encounter was the only large-scale clash of battleships during the war. It isn't clear from the letter whether the future George VI felt it had been a victory or a defeat. In the event, the British lost 14 ships and more than 6,000 men, and the Germans lost 11 ships and more than 2,500 men. "I was distinctly startled and jumped down the hole in the top of the turret like a shot rabbit!!" the prince writes at one point.

Letter from Queen Elizabeth to Queen Mary about German bombing, 13 September 1940

Image copyright Royal Archives

Buckingham Palace was bombed nine times during WW2, and suffered considerable damage. It is commonly seen as a great morale booster for Britain that members of the Royal Family stayed in residence, and shared the experience of so many Londoners during the Blitz. Towards the end of the letter, Queen Elizabeth writes: "It does affect me seeing this terrible and senseless destruction - I think that I really mind it much more than being bombed myself. The people are marvellous, and full of fight."

Princess Victoria's paper dolls, circa 1830

Image copyright Photograph: The Royal Collection

The pictures were based on Princess Victoria's own doll collection, painted and then cut out and stuck in her journal. "The young Princess Victoria's governess Baroness Lehzen probably made the outlines, but the colours and designs are likely to be Victoria's own," says Ms Porter.

Written by David Prest, executive producer of BBC Radio 4's UK Confidential