>>35601
>Sounds interesting. I wonder what's behind the lack of info
The information is out there, buried in some library with no way to access from Libgen or Google Books. There's just not enough interest. Usually a comprehensive description of a past hierarchy is only compiled in case of a formal war, which hasn't been the case since the 1860s. In peacetime fragmented information about the hierarchy shows up when scholars dig up the military's history, but I've found few information in those cases as civilian and military historians are mostly concentrated in either the social and political context or the development of doctrine and commanders' biographies.
>Those Roman numbers sounds like military districts or corps. Or military districts that convert into corps in case of mobilization. Armies traditionally signaled by Arabic numbers, similar to divisions.
The sources I've found call them by Roman numbers.

>What was the ideological split? Since it's Cold War era I can guess.
Some factors were unique to the military. It already had a tradition of insubordination as insubordination was what had brought the Republic into existence in the first place. The existing (Fourth) Republic by then was also brought about by a military-civilian movement which toppled Vargas. Attempts at military interference in politics, with civilian backing, continued through the 50s. Then in 1961 there was once again an institutional crisis. The elected President, Jânio Quadros, published a cryptic resignation letter in a bungled move to return to power with popular support. Nobody moved in his favor. Though backed by the right, he was more of a meme President than anything and doesn't fit neatly into the ongoing power struggle. The real problem was a peculiarity in the existing electoral system: the offices of President and Vice-President were elected separately. Jânio's VP was a leftist of the more confrontational kind and would now step in. A military-civilian movement to prevent his accession to power was thwarted by a strong civilian reaction and, within the military, by widespread legalism (Mourão Filho himself and other 1964 rebels were legalists in 1961), specially among sergeants. The crisis was resolved by transitioning to a parliamentary system which emptied Jango's power.

This crisis had a lasting impact in the military. Sergeants and sailors had become politicized in Jango's favor. Hierarchy was giving way to anarchy.
Some units lived in a kind of double command. Hundreds of officers withstood embarrassing situations. In a unit at the Vila Militar there were sergeants who disregarded timetables and held private depots. One of them threatened the "reactionary sirs": "the instrument of labor of military men is the rifle". Another, elected a Deputy, spoke of the "hanging of those responsible for the tyranny of economic powers". In 1963 leftist general Osvino Ferreira Alves, the foremost "general of the people", celebrated his birthday with a party attended by eight hundred sub-lieutenants and sergeants. Sailors used the ships' transmission network to communicate their slogans, and, at least once, opened the Admiralty Council's safe to copy minutes from a secret meeting.
(Elio Gaspari, A Ditadura Envergonhada)