The Kanalkampf was the German term for air operations by the Luftwaffe against the Royal Air Force (RAF) over the English Channel in July 1940, beginning the Battle of Britain during the Second World War. By 25 June, the Allies had been defeated in Western Europe and Scandinavia. Britain had rejected peace overtures and on 16 July, Adolf Hitler issued Directive 16 to the Wehrmacht, ordering preparations for an invasion of Britain, under the codename Unternehmen Seelöwe.