Aecio
In the Western Roman Empire, a "commander-in-chief" evolved with the title of "magister utriusque militiae" often abbreviated MVM. This powerful office was often the power behind the throne and was held by Stilicho, Flavius Aetius, Ricimer, and others. In the East, there were two senior generals, who were each appointed to the office of "magister militum praesentalis".