After taking part in the capture of Rome in 1870 , in 1877 he was promoted to Major General, then Lieutenant General in 1883 , until he obtained command of the Alexandria division . In the colonial field he was governor of Massawa in Italian Eritrea from 1887 to 1888 and commander in chief of the great expeditionary force sent to East Africa after the Dogali disaster Battle of Dogali. San Marzano guided his troops with caution and successfully faced the Ethiopian army which eventually had to retreat due to logistical difficulties.