Military Organization and Terminology

[JasonC]

Michael - it is basically French, it dates especially from the levee en masse of the revolutionary armies, made systematic by Napoleon. Originally regiments were "demi brigades" in that system, which made the higher echelons systematic, usually as twos and occasionally as threes. An old royal regiment would put 2 battalions into the field as a demi brigade; a brigade would pair two of those; a division would pair two of those (and add a bit of artillery). The army corps, which dates only to about 1804-5 as a standing rather than ad hoc organization, would pair two of those and add some cavalry.

Other nations mirrored that system, the Prussians in their reorganization after their defeat at Jena, using a triangular rather than binary system, with the third battalion (sometimes more) militia (landwehr) rather than regulars, and the division level omitted (since a triangular brigade was actually larger than a binary division, at 9 battalions rather than 8. Notice that later this was the same structure used in triangular divisions, with a mere terminological difference that the 9 battalion formation was called a "brigade" rather than a division).

The American military has always learned from the French. That dates to the revolutionary period, and since the army practically ceased to exist in the later 19th century (after the civil war, where Napoleonic systems were the main model), happened again in WW I.

The British kept their old regimental traditions throughout, then overlaid the rationalized modern forms on them, but strictly for higher echelons.

The more rationalized and uniform modern systems became the standard for the rationalized bureaucratic states of the 19th century and the larger armies they could field, as logistics improved. By WW I, some of the formations had become huge, with four subelements per step level in many cases. These were then used in rotations to deal with the greater wastage and fatigue modern artillery warfare inflicted on the poor bloody infantry. In WW II, triangular formations were a streamlining of that bloat, and later in that war some went back down to binary to keep support arm levels at higher ratios to infantry, or stretch out trench strength.