History: Wild West By Timothy H. O'Sullivan

Timothy H. O'Sullivan (c. 1840 – January 14, 1882) was a photographer widely known for his work related to the American Civil War and the Western United States.
O'Sullivan was born in Ireland and came to New York City two years later with his parents. As a teenager, he was employed by Mathew Brady. When the Civil War began in early 1861, he was commissioned a first lieutenant in the Union Army (Joel Snyder, O'Sullivan's biographer could find no proof of this claim in Army records) and, over the next year, was present at Beaufort, Port Royal, Fort Walker, and Fort Pulaski. There is no record of him fighting. He most likely did civilian's work for the army such as surveying, and he took photographs in his spare time.