For years, the French had been aware of intelligence indicating that Germany planned to attack France through Belgium. General Joseph Joffre, chief of staff of the French military from 1911, inquired about the possibility of moving some French troops into Belgium to pre-empt such a move by Germany, but France's civilian leadership rejected this idea. Joffre was told that France would not be the first power to violate Belgian neutrality and that any French move into Belgium could come only after the Germans had already invaded. On 2 August, Germany occupied Luxembourg, and on 3August declared war on France; on the same day, they sent the Belgian government an ultimatum demanding unimpeded right of way through any part of Belgium, which was refused. Early on the morning of 4August, the Germans invaded; King Albert ordered his military to resist and called for assistance under the 1839 Treaty of London. Britain demanded Germany comply with the Treaty and respect Belgian neutrality; the ultimatum expired on 4 August at midnight Berlin time, 11pm British time. No reply having been received by then, Britain was at war with Germany.