Maximilian and his chief supporters were taken prisoners, May 15, 1867. This information was received in the United States toward the last of the month, and along with it a report, not well authenticated and which afterward proved to be false, that they had been executed on the 16th. As soon as these rumors reached Washington, Mr. Seward telegraphed to Mr. Campbell, then at New Orleans, June 1, 1867, directing him to proceed at once to the residence of the President of Mexico and enter on his mission, and if necessary to urge clemency to Maximilian and the other prisoners of war. Mr. Campbell failed to act under these instructions. He requested first that a public vessel of the United States should be detailed to carry him to Mexico. When it was found that no ship was available for this purpose, he was ordered to proceed to Havana and thence by the British or French line of steamers to Vera Cruz. He replied that under the circumstances he did not think it becoming the dignity of the representative of the United States to return to Mexico under the flag of a nation which had shown such hostility to that country. He thus remained at New Orleans from the first to the fifteenth of June. He was then ordered peremptorily to proceed at once according to instructions. He replied that he was ill and was afraid to go by way of Havana, where yellow fever was raging; that he would resign, if desired. The same day Mr. Seward telegraphed him that his resignation would be accepted.
Mr. Seward then informed Mr. Romero, the Mexican minister at Washington, that Austria, France, and Great Britain had appealed to the United States to use its good offices to avert the execution of Prince Maximilian. He strongly recommended clemency to President Juarez, as good policy, and requested Mr. Romero to make the same known to his government at once. This was June 15, the same day that Mr. Campbell's resignation was accepted. On the 21st, Mr. Seward requested Mr. Romero to inform President Juarez that the Emperor of Austria would restore Maximilian to all his rights of succession upon his release and renouncing forever all projects in Mexico.[243]
Meanwhile Maximilian of Hapsburg, Miguel Miramon, and Tomas Mejia had been tried by court-martial and sentenced to death, June 14. The sentence was confirmed by the government on the 15th, and the execution fixed for the 16th, but at the request of Maximilian's counsel, it was suspended by order of President Juarez until the 19th, in order to allow the prince to arrange certain business affairs of a private character. At seven o'clock on the morning of June 19 the prisoners were shot.