I got bored with the work I was doing so I side-tracked onto this for a little while! The big question here is how pedantic do you want to be about the details of this creation? If you’re creating a novel then readers of a story want just that – a good story – not a lot of geeky detail about ranks and insignia. For the sake of developing this discussion, however, I would consider both the likely characters around your King and the separate concepts of the ranks of nobility, Royal administrative posts and military “ranks.”
The ideas outlined below are very mediaeval and feudal. I guess they may not sit so well with your concept of modern military technology alongside a pseudo-feudal political structure. The increasing complexity of war almost demanded the creation of standing armies, led by professional officers instead of nobles: learning horsemanship and swordplay or archery on the village green is one thing but a tank requires munitions and fuel and skilled engineers to maintain it, the same goes for fighter jets. It also requires a very different sort of industrial economy, which probably wouldn’t function effectively if wealth and power was being brokered by a small number of families. You’ll have to think about how you might get all of this to work together in your created world!
Please feel free to use any or none of this as it suits you; I fully accept that it’s much more aligned to a world of swords and horses than a futuristic sci-fi feudal system but it’s just one idea as to how such a society might be structured. I know I haven’t incorporated your differential in terms of rank titles between the Army and the Royal Guard but I kinda wanted to throw in some slightly different thoughts and, if nothing else, it will hopefully stimulate some further ideas on your part. OK, here goes:
The Monarch – Hereditary ruler. ‘nuff said, no arguments!
The Nobility
You can take your pick from established (or newly created) titles for the various ranks of nobility. In such a system there inevitably exists a “pecking order” or degrees of seniority. Many old noble Houses may have histories much longer and more significant than some of the others (including even the ruling Royal house) – this comes into play with the politics of the Kingdom and the level of influence individuals may wield at Court. The feudal nobility is hereditary; the oldest son inherits the title, land, rights and responsibilities of his father. Grants of land and lesser titles may be made to second and subsequent sons. Lesser sons may find more opportunity for advancement at Court, perhaps by joining the Royal Guard as officers. All nobility is, in theory at least, the prerogative of the Monarch but, depending on the security of their own power-base, it may be a very foolish monarch who tries to remove the lands and titles of an ancient family – wars have been fought (and lost!) over less…!!
The example below is adapted from established (British) noble hierarchy of feudal and later times. Obviously any or all of these titles may be amended or replaced by new ones but you should get the general idea.
Prince – usually the title given to a son of the King. It may also be a title in its own right for the head of an ancient noble House (whose own sons will also be princes).
Duke – a very ancient and senior degree of nobility, held to be of equal rank to a prince; often old established Houses with strong roots in one part of the country.
Earl (or Count) – another old title but superseded in seniority by that of Duke.
Viscount – a lesser version of an Earl (or Count) – usually a more recent grant and generally with less land and a smaller requirement in terms of providing men for military service.
Baron – the lowest rank regarded as being a noble.
Knight – an ennoblement but not a hereditary title. It generally carries the responsibility of small a grant of land and the requirement to give military service with a number of men when called to do so by an overlord. Knighthood is an honour and implies a certain skill at arms and also a level of duty. The sons of nobles may inherit titles and land but they must still be raised to knighthood, regardless of their noble rank (although, obviously, this is usually something of a foregone conclusion!). Any knight may make a knight but there is greater honour in being knighted by more prestigious knights (of prowess at arms or of more noble seniority) or, obviously, by the King.
The senior establishment at Court:
These roles are just a few of the likely characters that would be involved; they are likely to be from noble families but will probably be picked for ability as well as political influence, so their own hereditary station may not be the highest.
Lord (High) Chamberlain – head of the domestic side of the Royal Household and organiser of the Court.
Lord (High) Chancellor – head of the administrative side of the Royal government (a sort of feudal Prime Minister). There will obviously be others on the staff of the Lord Chancellor to take on certain sub-roles of his office (a sort of feudal cabinet). The day-to-day administration will likely run without the direct intervention of the King.
Lord (High) Marshal – head of the Royal Household Guard and also chief military advisor to the King (a sort of feudal Secretary of Defence and also military Chief of Staff). He may or may not be appointed Captain-General of the army, depending on the nature of the campaign being undertaken and the size of the force in the field.
Lord (High) Justice – the chief judge and law officer of the kingdom. Day-to-day he administers the law with Royal Authority but the King has the final say! Subordinate Royal Justices will be placed around the Kingdom but, again, final say will rest with the local feudal overlord. In remoter areas, the overlord himself will be the Royal Magistrate.
The Royal Guard
The regular soldiers of the Guard will be regarded as
"chosen men" and, relative to conscript peasants in the army
pro-tem, they would automatically be regarded as
Corporals or
Serjeants.
The senior Serjeants of the Guard would effectively be Warrant Officer/Sergeant-Major types: efficient, experienced veteran professional soldiers who are well regarded by their officers. (The older spelling of "serjeant" is deliberate.)
Many (probably most) of the “officers” of the Guard will inevitably come from various noble families. They may be described as
"Knight-Captain (of the Guard)" regardless of any actual noble ranks they may hold. This rank would be roughly equivalent to contemporary company grade officers but there would likely be little distinction in terms of titles or uniforms – these officers know each other and seniority will likely be determined by which company of guards they are appointed to – a bit like Roman centurions working their way up from the last cohort of a legion to the first. (Perhaps referred to as Knight-Captain of the 1st, 2nd, 3rd…? The title of
"Sub-Captain (of the...)" could be used for young nobles, new to the Guard and just appointed to their Companies.)
Their unit commanders would be
"Knight-Marshal (of the Guard)" a rank perhaps equivalent in stature to modern field grade officers. Again, this would be irrespective of any noble title they hold and seniority between them would be determined by convention and appointment. These officers will report to the Lord Marshal and the senior of them will deputise for the Lord High Marshal in the day-to-day running of the Guard (
First Knight-Marshal perhaps…?).
Around the Kingdom:
The Reeve (note: an old English term – the “Shire Reeve” ultimately became “Sheriff,” shire being a rough equivalent of County) is a noble appointed by the King to exercise the Royal authority in an established part of the realm. The title
Lord Provost may be used for a similar role in larger towns and cities. As a general rule, they would report through the Lord High Chancellor. In more remote areas the Reeve will also be the Royal Magistrate, dispensing the King’s Justice. In bigger settlements, the Lord Provost will likely have a Royal Justice as part of his staff to undertake this role but he may have the final say. The Reeve would also be responsible for commanding and maintaining a militia from the knights and nobility within his area; in these matters he would report to the Lord High Marshal. In time of war, he may or may not retain command of that militia, depending on operational requirements or other appointments he may be given. A Lord Provost is responsible for the security of his city and will raise and organise the City Watch, under a
Watch-Captain and
Watch-Serjeants.
Senior nobles from important families would usually have a long traditional association between their House and a recognised geographical area. They will generally be their own Reeves, with direct authority from the King, and will raise their militias from their subordinate nobles and knights, with associated peasantry as footsoldiers. A senior noble with a large household and a big tract of land to manage will likely have his own Chamberlain, his own Chancellor and his own Knight-Marshal to head his own professional household guard and organise the local militia (possibly with Knight-Captains under him if it’s a big household guard or maybe just a Knight-Captain if it's smaller). Again, in a time of general mobilisation, the nobles will likely get jobs that we would now recognise as senior staff officer posts and the professional Knight-Marshals may get the equivalent of regimental command roles, under the Lord High Marshal, or whichever noble was appointed as the Captain-General. If the nobles are given senior command roles then I would expect their Knight-Marshals to stay with them, effectively acting as their chiefs of staff within that command.
The Army
All military appointments, with the exception of those of the standing forces of the Royal Guard (and other household guards), are temporary and describe a ROLE within the deployed force rather than a substantive “rank” as we would understand them. I would suggest that many of the “officer” roles will inevitably be allocated to nobles and knights, according to seniority – although you can obviously make exceptions for characters of lesser degrees of nobility who, perhaps, have notable histories of proven command ability. Overall, the army
pro-tem will have a relatively “flat” rank structure – the nature of feudal government is that significance and seniority is determined by political influence and appointed role as much as by rank title.
Captain-General
The commander of the army in the field. In practice, the role of Captain-General may well be appointed to an influential senior noble, probably for political reasons. Alternatively, if they are old enough, the Captain-General could possibly be a son of the King. All of this will leave the Lord High Marshal free to be an independent advisor to the King and also to command and retain the loyalty of the Guard, separate from the army as a whole (always a useful fail-safe for a monarch!). Depending on the situation, I guess it could be possible to have a
Captain-General of the Armies of the West, Captain-General of the Armies of the North, and so on, in which case the Lord High Marshal might act as a co-ordinating Chief of Staff between them.
Other senior command roles:
Marshal of Horse, Marshal of Foot, Provost-Marshal, etc…
These are almost always nobles but will inevitably have some proven experience in these roles.
“Field” grades:
Marshal of the (insert name of area Militia or other unit here).
Usually nobles or knights but may also be from the more influential families of the landed gentry. There may be scope for a
"Lieutenant-Marshal" as a supernumary second-in-command of larger units or, perhaps a
"Captain-Major" who would be commander of the first company and also acting as second-in-command. The
Serjeant-Major would be the right-hand of the Marshal for administration and discipline among the common soldiers.
“Company” grades:
Captain of the (1st, 2nd, 3rd…) Company of… etc.
Sub-Captain of the same (where required).
Sometimes lesser nobles (or their sons) or knights, depending on the significance or seniority of the role, but also drawn from the landed gentry.
Other ranks:
Serjeant
Corporal
Common soldier
That's it for now - adapt or ignore this as you choose!