In 1859, a 19-year-old man named Kossola was captured, chained and brought on the last US slave ship from West Africa to Alabama. He would eventually regain his freedom at the end of the Civil War in 1865. Near the end of his life in the 1920s, he recounted his experiences of the trans-Atlantic slave trade for a book — which lay unpublished until just last year. Ashley Byrne went to find out more.