Several armies tried scrapping military ranks entirely, and every one brought them back
Communist governments have occasionally tried running armies without formal ranks. The Soviet Red Army went without them from 1918 to 1935, China's People's Liberation Army from 1965 to 1988, and Albania's forces from 1966 to 1991. Each time, command and control ran into trouble, and the insignia eventually returned.
Ancient Athens offered its own unusual model. From 501 BC citizens voted each year for ten generals, called strategoi, one per tribe of the new democracy. None outranked the others. The role of polemarch, the old war leader, rotated among them one day at a time, and that day's holder broke any tie. Before the Battle of Marathon in 490 BC, the generals chose their battle plan by majority vote.
Athenian ships had their own titles. Each warship answered to a trierarch, a word meaning trireme officer that stuck even after other vessels appeared. Beneath him, a helmsman steered, another officer set the rowing pace, and a flute player piped the rhythm for the oarsmen. Later a dedicated sea commander, the nauarchos, took over naval leadership, roughly an admiral.
Rome treated command as political and even religious. Only someone holding imperium, usually a consul, could lead. His deputy was a legatus, a term meaning proxy or envoy; linking it to the word legion is a folk etymology. Senators typically served as legates for three years. Below them sat six military tribunes, and third in the legion was the camp prefect, usually a promoted former centurion, a split resembling today's divide between commissioned and non-commissioned officers.
Marius's reforms set the legion's ladder: ten cohorts, each of three maniples, each of two centuries holding between 60 and 160 men, with the century split into ten tent groups of eight. The senior centurion was the primus pilus. Far to the east, steppe armies relied on a strict decimal structure rather than titles, a system used by Modun Chanyu: squads of ten, companies of a hundred, regiments of a thousand and units of ten thousand called tumens.
Source: Military rank
