Colonel Arthur Fremantle was twenty-six and on a leave from official duty when he rather impulsively decided to observe the Southern rebellion for himself. As he described in Three Months in the Southern States, Fremantle was able to observe both the rebellion and many of its major leaders.

Landing near the mouth of the Rio Grande, Fremantle crossed Texas, meeting an aged Sam Houston along the way. Passing through Mississippi, he met General Joseph Johnston, whom he found very pessimistic about any attempt to relieve the garrison at Vicksburg. Much intrigued by the institution of slavery, Fremantle noted that in Texas a healthy male slave often sold for $2,500, but that a skilled seamstress would sell for as much as $3,500. Fremantle visited Mobile and Montgomery on his way to the Eastern front; he was one of the first to describe the Confederate battle flags, which he described as quite worn and tattered when compared to the captured Yankee ones. Fremantle arrived in Virginia in time to accompany the Army of Northern Virginia on its way north. At times when reading Fremantle’s diary, one is led to ask: Can one person really have met so many people in so short a time? His record is backed by enough corroborative evidence, however, that the historian gives Fremantle full credit for most of his observations.