The Sikorski Institute was established on 2 May 1945 as an independent public use institution operating under British law. Polish civilian and military authorities were not formally involved in the establishment of the Institute - in this way it was hoped to safeguard its collections against claims by the Communist government from Warsaw. Its primary task was to acquire and safeguard the archives of Polish military and civilian institutions operating in exile and the memorabilia left behind by the Polish Armed Forces in the West. The Institute is housed in a townhouse at 20 Prince's Gate, purchased with public donations in 1946. It is a prestigious location on the border of the London boroughs of South Kensington and Knightsbridge, in close proximity to Hyde Park and the Royal Geographical Society. The five-storey building with a usable attic was built in the mid-19th century in the distinctive style of the Victorian era. It forms part of a string of a dozen or so similar townhouses that initially served mostly as residences for London's wealthy bourgeoisie, and over time became the headquarters of various institutions. The origins of the museum were the legacy of General Władysław Sikorski, bequeathed to the Institute's founders by his widow, Helena Sikorska. After the dissolution of the Polish Armed Forces in the West, banners and other militaria found their way to Prince's Gate. Over the years, the museum's collection also expanded with gifts from politicians and soldiers who remained in exile after 1945. Among the exhibits, the first to be mentioned are several dozen banners. Most of them are banners of units of the Polish Armed Forces in the West, but there are also a few saved from the September campaign. These include, for example, the banner of the 14th Cavalry Lancers Regiment, first miraculously saved during the charge at Wólka Węglowa on 19 September 1939, and later kept in Warsaw during the occupation and the Warsaw Uprising. Also standing out from the memorabilia of the Polish Armed Forces in the West is the banner of the 1st Independent Parachute Brigade, sewn at the request of General Stanisław Sosabowski in occupied Warsaw and delivered to the UK in the spring of 1944 as part of Operation Bridge I. In addition to the banners, one can also find the white and red flag and the pennant of the 12th Podolski Lancers Regiment, displayed on the ruins of the Monte Cassino monastery immediately after its capture. The museum also has hundreds of other artefacts, ranging from decorations and small personal mementos to uniforms and weapons and works of art. These include such unique objects as the map of the Baltic Sea drawn from memory by Lieutenant Marian Mokrski, thanks to which the submarine ORP 'Orzeł' successfully made her way to the UK after escaping internment in Estonia. The archive at Prince's Gate contains 2,000 linear metres of files. At their core are documents of the Polish Government in Exile and the Commander-in-Chief, the General Staff and individual units of the Polish Armed Forces in the West. A separate and extremely valuable collection is the collection of accounts of the September campaign, which is the most important set of sources for the history of the 1939 defensive war. The archives of the Sikorski Institute also contain a collection of documents of state institutions of the Second Republic evacuated from Poland in September 1939 and later from France in 1940. Finally, mention should be made of the hundreds of private collections bequeathed to the Institute by donors. They contain the legacy and personal mementos of, among others, General Władysław Sikorski or General Władysław Anders.