Joseph Joffre Germany occupied Luxembourg Albert I of Belgium Treaty of London ultimatum Germany France Britain
Aware of German plans to attack through Belgium, French Commander-in-Chief Joseph Joffre asked his government for permission to cross the border and pre-empt such a move. To avoid a violation of Belgian neutrality, he was told any advance could come only after a German invasion. On 2 August, Germany occupied Luxembourg and exchanged fire with French units; on 3 August, they declared war on France and demanded free passage across Belgium, which was refused. Early on the morning of 4 August, the Germans invaded and Albert I of Belgium called for assistance under the Treaty of London. Britain sent Germany an ultimatum demanding they withdraw from Belgium; when this expired at midnight without a response, the two empires were at war.
