About eighty passengers, including American citizens, were killed or wounded.
Several notes passed between our government and Germany on the sinking of the Sussex and other vessels.

Our ambassador at Berlin was instructed to take energetic action and to insist upon adequate attention to our demands.

April 18 our government delivered what was considered an ultimatum to the effect that unless Germany abandoned her methods of submarine warfare, the United States would sever diplomatic relations.
The president addressed congress on the matter the following day.
Germany had not yet completed her program of submarine building and thought it wise to temporize with the American government for a while longer.

May 4 she replied to the ultimatum of April 18, acknowledged the sinking of the Sussex and in the main acceded to all the demands of the United States.

There were certain phases which indicated that Germany wished to use this country as a medium for securing certain agreements from the Allies.