Mr. Roosevelt had determined to resign his position in order to take active service in the field. His adventurous nature would not allow him to remain in an office when there was a prospect of fighting for the flag. He had determined to organize a regiment of Western men, whom, he rightly believed, would strike terror to the hearts of the Spaniards. Mr. Roosevelt’s resignation as Assistant Secretary of the Navy bears date of May 6, 1898. His appointment as lieutenant-colonel, First Regiment, United States Volunteer Cavalry, is dated May 5, 1898. The First United States Volunteer Cavalry was one of the most remarkable fighting aggregations ever enlisted in any country. It was chosen from some 3,500 applicants and numbered about 900. The plains gave it its largest membership, and the name under which it soon came to be known was “Roosevelt’s Rough Riders.” Dr. Leonard Wood, a United States Army officer, and a close friend of Colonel Roosevelt, was made colonel of the regiment. Colonel Roosevelt believed he was not sufficiently well informed concerning military matters to handle the regiment during the preliminary work, and he readily acquiesced in the appointment of his friend. The regiment rendezvoused at San Antonio, Texas, and there was kept at work learning the discipline of soldier life, until it was finally called to the front. Among the recruits were hundreds of cowboys who were perfect horsemen as well as dead shots. But such an outburst of popular interest attended the recruiting of this regiment that Colonel Wood and Lieutenant-Colonel Roosevelt were soon overwhelmed with applications for enlistment from the college men, athletes, clubmen, sons of millionaire parents, who loved the idea of adventure and battle in such company. As a result several companies were recruited from the pick of the young men of the country. Nearly every noted club of the country had its quota, and scores of Wall street stockbrokers wore khaki in the ranks. When finally the regiment was gathered at Tampa, Florida, it constituted a body of men than whom it would be hard to find any more perfectly fitted for such war as the conflict with Spain in the jungles of Cuba assured. Old Indian fighters were there by the score, and there were even six full-blooded Indians among the enlisted men.