Russia demanded assurances from Austria that war was not forthcoming and it continued to mobilize.

On August 1, Germany declared war.

France then began to mobilize.
Germany invaded the duchy of Luxemburg and demanded free passage for its troops across Belgium to attack France at that country's most vulnerable point.

King Albert of Belgium refused his consent on the ground that the neutrality of his country had been guaranteed by the powers of Europe, including Germany itself, and appealed for diplomatic help from Great Britain.

That country, which had sought through its foreign secretary, Sir Edward Grey, to preserve the peace of Europe, was now aroused.
August 4, it sent an ultimatum to Germany demanding that the neutrality of Belgium be respected.