Complex sentence: Arthur was promoted to the honorary rank of colonel on 14 June 1871, as a lieutenant-colonel in 1876, a substantive colonel on 29 May 1880, and on 1 April, 13 years later, was made a general.
Split into simpler sentences: Arthur was promoted to the honorary rank of colonel on 14 June 1871. The Prince was promoted to the substantive rank of colonel on 29 May 1880 and, on 1 April, 13 years later, was made a general.