Andrew Johnson (December 29, 1808 –  July 31, 1875) was the 17th president of the United States, serving from 1865 to 1869. He assumed the presidency as he was vice president at the time of the assassination of Abraham Lincoln. Southern slave states seceded to form the Confederate States of America, including Tennessee, but Johnson remained firmly with the Union. He was the only sitting senator from a Confederate state who did not resign his seat upon learning of his state's secession. In 1862, Lincoln appointed him as military governor of Tennessee after most of it had been retaken. In 1864, Johnson was a logical choice as running mate for Lincoln, who wished to send a message of national unity in his re-election campaign; their ticket easily won.