So Why Does a Lieutenant General Outrank a Major General?

Well, it's a bit complicated.

Aside from a few men to guard the royal person and some critical castles, prior to the fifteenth century most countries did not have standing armies. When war came, the king would call for troops, often using a combination of feudal levies, paid contractors, and mercenaries, who were often feudal lords commanding their own vassals. But in the late fifteenth century the kings of France and of the Spains began keeping a larger body of troops on the royal payroll even in peacetime, primarily to preserve internal order.

These were organized into "companies" of vaguely similar size, each of which was commanded by a "captain," a word deriving from the Latin and meaning essential "head." Assisting the captain was a lieutenant, deriving through French from the Latin locum tenens, which means "in place of the holder [of command]." Now since these companies were initially composed of mounted troops -- men-at-arms -- the individual soldiers were all "serjeants," essentially unknighted knights. So the next lowest ranking man in the company was the "sergeant major."

When an army was needed, a bunch of the companies was ordered to report to an officer appointed as the "captain general," who would command them in action. Of course with so many individual companies under his command, the captain general had a lot to do. So early in the sixteenth century, King Ferdinand of Spain (Columbus' friend), grouped batches of ten companies into colunelas --columns -- under a capitan de colulnela, thus creating the first regiments. He also created the basis for the modern rank structure The colunelas worked pretty well in combat, as the captain general now had a lot fewer subordinates to deal with. Within his colunela the capitan de colunela -- the "colonel" -- had several subordinates, notably a teniente de colunela and a sergente mayor de colunela. And within his army, the captain general also had some subordinates, a teniente general and a sergente mayor general.

On each level, the role of the officers was the same:

Rank (in Spanish)	Assignment
capitan, capitan di colunela, capitan general	The commanding officer
teniente, teniente di colunela, teniente general	Deputy commander
sergente mayor, sergente mayor di colunela, sergente mayor general	Management of the troops

With changes in spelling to account for language differences, the Spanish usage spread to the other armies in Europe. And it from these roots that modern rank structure developed.

Evolution of the Rank Structure
Original Spanish	Modern English
capitan general	general
teniente general	lieutenant general
sergente mayor general	major general
capitan di colunela	colonel
teniente di colunela	lieutenant colonel
sergente mayor di colunela	major
capitan	captain
teniente	lieutenant
sergente mayor	sergeant major

There are, of course, some other ranks. The differentiation between first lieutenant and second lieutenants -- and in some armies even third lieutenants -- was an evolutionary matter. The brigadier general is named after a non-commissioned officer rank found in some Latin armies, the brigada or brigadier , who was the principal subordinate of the sergeant major. It seemed reasonable to call the commander of a group of regiments by this title because he would be directly subordinate to the sergeant major general of the army. Eventually, of course, the commander's title became the name of his command, the brigade. In German and Russian usage there is a "colonel general." But these armies lack a grade between colonel and major general, so the colonel general actually ranks with a full general.