Complex sentence: During the American Civil War, Union troops tried to build a canal at Dutch Gap late in 1864 to cut off a large curl of the James threatened by Confederate forts such as Battery Dantzler.
Split into simpler sentences: During the American Civil War, Union troops tried to build a canal at Dutch Gap late in 1864. The Union Army intended to cut off the large curl of the James threatened by Confederate forts, such as Battery Dantzler.