place between the military and naval staffs of Sweden and Germany on cooperation, and preliminary arrangements were made for Germany to use bases and anchorages on the east coast of Sweden and on the island of Gotland. Wallenberg also warned the Germans that Sweden could not intervene too soon as this might prompt a British intervention in the conflict, although this in turn led the German minister in Stockholm, Franz von Reichenau, to suggest that if Britain entered the conflict Germany should issue an ultimatum demanding that Sweden join the war. At the same time messages were sent by the Swedish foreign ministry to Russia promising that Sweden would remain neutral, although troops were sent to watch Sweden's frontier with Russian-ruled Finland. Declarations of Neutrality Sweden declared neutrality in the Austro-Serbian conflict on 31 July 1914, and in the general conflict of Germany against France and Russia on 3 August. Both declarations left open the possibility that Sweden might later change her position if other countries joined the conflict. On 2 August, however, Wallenberg, speaking to the British minister in Stockholm, had repeated his assertion that if Sweden were driven into the war, she would never fight on the side of Russia. Apparently fearful that Germany might issue an ultimatum demanding Sweden choose sides (something the German Kaiser had threatened to do during a visit by King Gustaf to Germany in 1913) Wallenberg also promised Franz von Reichenau that Swedish neutrality would be "benevolent" to Germany. The position of Norway also concerned Wallenberg, as he believed that the Norwegians would prefer to intervene on the British side if they entered the war. On 8 August the two countries (Sweden and Norway) issued a joint declaration of neutrality warning that they would maintain their neutrality against all belligerents and would guarantee each other's neutrality. A further joint declaration was made by the three kings of Denmark, Norway, and Sweden in December 1914, and the Swedish army units that had been sent to the Finnish border were stood down. Germany offers an alliance In early 1915, Arthur Zimmermann, the Under-Secretary of State at the German foreign ministry, approached Hammarskjöld, who was on a visit to Berlin, with an offer of potentially forming a "Nordic Block" under Swedish leadership in return for an alliance between Sweden and Germany. Whilst Hammarskjöld rebuffed this first offer, Zimmermann persisted and approached Ludvig Douglas with an offer