Complex sentence: Although only 15 at the time of his enlistment, Chen would quickly rise through the ranks because of his bravery and demonstrated tactical skills and by 1856, in the aftermath of an internal power struggle within the Taiping leadership, Chen was promoted to a general.
Split into simpler sentences: Although only 15 at the time of his enlistment, Chen would quickly rise through the ranks because of his bravery and demonstrated tactical skills. By 1856, in the aftermath of an internal power struggle within the Taiping leadership, Chen was promoted to a general.