The United State's involvement in the European Theatre of the Second World War did not commence until mid-1941 with Lend-Lease, and direct, open participation did not begin until the U.S. Navy began engaging the Kriegsmarine in the fall of 1941, months before Pearl Harbor, by which time Enigma machines had already been captured and their codes broken in Europe. An earlier military Enigma had been examined by Polish Intelligence in 1928; the Polish Cipher Bureau broke the Enigma code in 1932 and gave their findings to Britain and France in 1939, just before the German invasion of Poland.