Queen Elizabeth II surpassed her great, great grandmother Queen Victoria as the longest reigning monarch last year, and on 21 April she celebrates her 90th birthday.

Monarchs such as Victoria and Elizabeth I are remembered as icons of a period of change. Their fashions were synonymous with the era of their reign. As a new and young monarch in post-war Britain, Queen Elizabeth II became the ruler of a country undergoing political, social and sartorial change.

Never before had fashion been so free and whilst of course no one expected her Royal Highness to step out in a pair of flares and Mary Quant mini, Elizabeth II has remained a stylish and sophisticated icon of British fashion throughout her life. She worked with fashion pioneers such as Norman Hartwell and Hardy Amies, as well as inspiring the likes of Dolce and Gabanna to base their autumn/winter 2008 collection around her.

Captured around the world and through the lens of everyone from Cecil Beaton to Annie Leibovitz, Elizabeth's style is individual to her and endlessly classic. Despite her utter dedication to professionalism and her role as monarch, the Queen has always managed to have a little fun with a wardrobe that has also managed to stay way clear of any form of seasonal disasters.

From the military feminist overalls of her Auxillary Territorial Service uniform in 1945 to her rather daring safari pant suit there are but a few occasions that she has strayed from her trusty fashion formula. Bold colours and perfect day coats worn with simple black patent slip-ons by Anello & Davide of Kensington as well as playful, albeit priceless, accessories and a luxurious classic Launer handbag are the staple ingredients of the Royal wardrobe. Not many people can claim their their style has remained relevant for nine decades.

As the Queen prepares to celebrate her ninetieth year in style, IBTimes UK looks back on her most fabulous fashion moments.

Queen 90th birthday
1928: Princess Elizabeth, aged two, in a ruffled layered party dress and pearls.The Print Collector/Print Collector/Getty Images
the Queen at 90
6th May 1937: The then Princess Elizabeth (L) and sister, Princess Margaret, leaving Westminster Abbey in their matching outfits, after a rehearsal for the coronation of their father as King George VI.Getty
Queen 90th birthday
8 July 1941: Princess Elizabeth (R) wears a broderie anglaise Peter Pan collar shirt and waistcoat whilst playing with sister Margaret and their pet chameleon in the grounds of Windsor Castle. Getty Images
the Queen at 90
30th June 1942: Princesses Elizabeth (L) and Margaret Rose dressed down in Girl Guide uniforms at Frogmore, Windsor, Berkshire.Lisa Sheridan/ Getty
Queen 90th birthday
23 December 1944: Princess Elizabeth dressed up for a production of Old Mother Red Riding Boots at home.Lisa Sheridan/Studio Lisa/Getty Images
Queen 90th birthday
18 April 1945: Princess Elizabeth is almost unrecognisable in overalls as she changes the tyre of a vehicle whilst training as an ATS Officer during World War Two.Central Press/Hulton Archive/Getty Images
the Queen at 90
8th July 1946: Princess Elizabeth, the future Queen Elizabeth II, chatting with her father, King George VI. Her tea dress embodies the simplicity of fashion in post-war England whilst still displaying her love of print and texture.Getty
the Queen at 90
July 1947: Princess Elizabeth poses in the state apartments in a simple shift dress with bow details with Prince Philip at Buckingham Palace upon their engagement.Getty
Queen 90th birthday
20 November 1947: Princess Elizabeth and Prince Philip pose at Buckingham Palace after their wedding ceremony which was held at Westminster Abbey. Like everyone else in the Uk at the time, the Queen had to save her clothing rations in order to have her dress made by the designer Norman Hartnell, which was worn with silk Raine sandals.Topical Press Agency/Getty Images
Queen 90th birthday
Circa 1950: A Cecil Beaton portrait of Princess Elizabeth in the drawing room of Clarence House in a Norman Hartnell gown. Hartnell was appointed official dressmaker for the Queen at the time.Bettmann Archive/Getty Images
the Queen at 90
17th October 1951: The Duke of Edinburgh dances with his wife, Princess Elizabeth, at a square dance held in their honour in Ottawa, by Governor General Viscount Alexander during their Canadian tour.Keystone/Hulton Archive/Getty Images
the Queen at 90
June 7, 1952: Riding side saddle and saluting during a Trooping of the Colour ceremony at Horse Guard's Parade, Central London. The Queen has worn military wear throughout her reign, always in the most sophisticated and elegant way.STRINGER/AFP/Getty Images
the Queen at 90
2nd June 1953: HM Queen Elizabeth II with her maids of honour in the Green Drawing Room at Buckingham palace. Following the example of Queen Victoria, Elizabeth chose six Maids of Honour instead of pages to bear her velvet train throughout the Coronation ceremony. The gown was designed by Sir Norman Hartnell.Getty
the Queen at 90
February 1954: In a slim-fitted lace design and black tulle and feathrered hat that would perhaps be more expected from her sister Margaret, Queen Elizabeth II looked absolutely beautiful as she attended a garden party in Sydney, Australia, before leaving for Tasmania on the liner 'SS Gothic'Keystone/Hulton Archive/Getty Images
the Queen at 90
1956: Queen Elizabeth II looks relaxed in a cotton A-line summer dress with Prince Charles at Windsor Great Park, during a polo match Hulton Archive/Getty Images
Queen 90th birthday
circa 1960: The Queen plays with her daughter Anne. Not often seen in trousers, the Queen looks very contemporary in a riding jacket and loose jodhpurs.Getty
the Queen at 90
1960: The Queen has often worn yellow to the races and looked wonderful in a typical sixties style cocoon coat with oversized buttons at the Epsom Downs Racecourse for the Oaks Stakes in Surrey.Fox Photos/Hulton Archive/Getty Images
the Queen at 90
Queen Elizabeth II looked effortlessly sophisticated in a royal blue tulle gown as she greeted President John F. Kennedy and First Lady Jackie Kennedy who were paying a visit to the royal family in England.Getty
the Queen at 90
November 1964: A fan of bold colour in evening and day wear, Elizabeth stood out in a coral silk gown as she attended a performance at the Royal Academy of Dramatic Art (RADA) in London. Getty
the Queen at 90
6th October 1967: Queen Elizabeth II walking cross country at the North of Scotland Gun Dog Association Open Stake Retreiver Trials in the grounds of Balmoral Castle. A silk headscarf and family tweed have long been the Queen's uniform when spending time at Balmoral.Getty
the Queen at 90
July 1970: The Queen braved the cold temperatures in style, wrapping up in a fur-trimmed jacket, as she visited Resolute Bay in Nunavut during a royal tour of Canada.Getty
the Queen at 90
July 11th 1970: Princess Anne and the Queen covered up uncharacteristically in Pantsuits for protection from the blackflies during a walk through Fort Providence; Northwest Territories in Canada.Doug Griffin/Toronto Star via Getty Images
Queen 90th birthday
14 October 1975: The Queen, a keen photographer, kneels down and watches the Badminton Horse Trials in a perfect mix of colourful tweed, block-colour pink turtleneck and classic Barbour.Anwar Hussein/Getty Images
the Queen at 90
February-March 1975: Queen Elizabeth II looks radiant in a vibrant yellow polka dot dress and turban as she meets a group of local children during her state visit to Mexico. White gloves and matching bag along with a diamond brooch and pearls have long stayed with her as everyday staples.Getty
Queen 90th birthday
1974: The Queen arrives at Aberdeen airport with her corgis to start her holidays in Balmoral. Her handbag by British brand Launer and handmade shoes by Anello and Davide of Kensington have remained the same style for over 50 years, whilst more contemporary additions such as the feather headpiece are typically 1970's.Anwar Hussein/Getty Images
the Queen at 90
February 1977: Queen Elizabeth II in Fiji during her royal tour in a drop waist summer dress and tulle detailed hat with Launer handbag and matching white gloves. Getty
Queen 90th birthday
May 1979: The Queen, wearing a dramatic but fitting pink cape and matching headscarf, whilst attending the Royal Windsor Horse Show.Tim Graham/Getty Images
the Queen at 90
1979: Queen Elizabeth II in one of her most contemporary looks in a paisley print shirt and aviator sunglasses as she goes on safari with Prince Philip during their state visit to Zambia.Serge Lemoine/Getty
the Queen at 90
15 February 1979: Queen Elizabeth II Exchanging Gifts With The Amir Of Bahrain,his Highness Shaikh Isa Bin Sulman Al Khalifa At Qudaibiya Palace in Bahrain. The coral hued lurex detailed gown is subtle and refined but still very seventies in style, although toned down with white gloves.Tim Graham/Getty Images
Queen 90th birthday
October 1982: The Queen and Prince Philip visit the Solomon Islands during a tour of the South Pacific. Queen Elizabeth wears a sky bloue skirt suit with floral detailed hat paired with her stalwart Launer bag and a pair of Anello & Davide white leather slip-ons.Anwar Hussein/Getty Images
the Queen at 90
October 14, 1989: Showing how Kate has followed in her footsteps, the Queen often mixed british designs with more traditional attire as she did when visiting the Shah Alam mosque in South East Asia. Touring the mosque with the architect Baharuddin Abu Kassim, the monarch wore a shimmering blue and gold silk robe with matching slippers.TORU YAMANAKA/AFP/Getty Images
the Queen at 90
4 August 1990: A floral fantasy for the Queen Mother's 90th birthday. The Queen, Princess Diana and Princess Margaret all dressed in vibrant, playful designs for the celebrations.Getty
Queen 90th birthday
2 April 2002: The Queen was dressed more somberly in headscarf and equestrian jodhpurs and rain jacket as she rode her horse in the grounds of Windsor Castle, three days after the death of her mother.Dan Chung
the Queen at 90
October 21, 2008: Queen Ellizabeth II paired her trusted Launer bag and Anello & Davide shoes with a bold blue coat with graphic fur trim and matching hat as she arrived with Prince Philip at Joze Pucnik airport on the first day of a two day tour of Slovenia.Getty
queen at 90
3 June 2012: The Queen waves to the crowds from the Spirit of Chartwell during the Diamond Jubilee River Pageant on the River Thames. Whilst not often one to wear white during the day, the Queen opted for a stunning ruffled edged coat with gold detailing and a starburst diamond brooch as well as white gloves.John Stillwell/Pool
queen at 90
1 September 2012: Laidback in lilac, the Queen joins Prince Philip and Prince Charles to cheer as competitors participate in a sack race at the Braemar Gathering in Scotland.Getty
the Queen at 90
July 5, 2012: Looking as sophisticated as ever in full regalia for the Thistle Ceremony in Ediburgh, Queen Elizabeth II smiles as she leaves St Giles Cathedral.Getty
the Queen at 90
July 11, 2013: Queen Elizabeth II enters The Mirrored House during the Coronation Festival in the garden of Buckingham Palace. In one of her most relaxed outfits, the floral shift dress and horsebit loafers are a perfect garden party pairing for any age.Getty
Queen 90th birthday
24 June 2015: Queen Elizabeth II looks as regal as she did for her coronation as she attended a banquet in Berlin during her four-day State Visit to Germany in a diamond tiara and ruby and diamond brooch and necklace.Michael Ukas