Is there a difference between “Your Grace” and “Your Majesty” in terms of deference and respect? Why is pre-conquest Westeros so uniform when it comes to royal styles?

Yes, and it has to do with fashions of royal address. According to Francois Velde of heraldica.org, “Your Highness” was the most common style across Europe from the 12th through 15th centuries CE. When Charles V became Holy Roman Emperor in 1519, he decided that he was too special to be a mere “Highness” – he did after all rule an empire that spanned from Asia to the Americas to eastern Europe – and instructed his court that he be described as “Majesty.”

Francois I of France, who would spend his entire reign fighting Charles V, wasn’t going to take this lying down and so insisted on also being referred to as “Majesty,” which led to a good deal of linguistic one-upmanship where Charles insisted on being called “Imperial Majesty” to Francois’ mere “Royal Majesty” and then Francois retaliated by using “Most Christian Majesty,” and so on. Henry VIII of England, who would be out-ego’d by no man, also began using “Majesty.” Just to confuse everyone, though, the English court continued to call him “Grace” and “Highness” as well as “Majesty” in legal documents, until the reign of James I, where it was regularized that the King is a “Majesty,” and Dukes and Archbishops are “Graces.”

So the TLDR is: a Majesty outranks a Grace.

To answer your second question, this is because GRRM wanted to simplify terms of address, the same reason that he used the same title of “lord” for everyone.

Would Garth “the Gross” Tyrell’s position as Lord Seneschal of Highgarden be as Mace’s treasurer given his consideration as Master of Coin, or more general administrator as a Hand equivalent, or something else?

Garth Tyrell is listed as the Lord Seneschal in the appendix. I was curious as to what exactly that means. And why is house Tyrell the only ones mentioned as having a Lord Seneschal?

Since I got a couple different asks on this subject, I thought I might as well tackle it in one place, as apparently I haven’t before.

The answer is that the text isn’t very clear about what the office entails. Nor does history eludicate matters, because the term can mean a number of different things:

Seneschal can mean “steward” (in the sense of official in charge of administration of the household) although that term doesn’t necessarily mean a high-ranking member of the servant class.
Second, “seneschal” was also an officer of a French (or more specifically Norman and Languedoc) administrative unit known as a seneschalty: seneschals governed the unit on behalf of the king but also acted as a chief justice or bailiff.

My guess, without much to base it off of, is that when the Tyrells replaced the Gardeners as Lords of Highgarden, they abolished the office of High Steward of Highgarden so as to prevent any comparisons being made between the incumbents and their predecessors. However, the work still needed to be done, so they created a new title for the old office so that they could use it as a cushy job for junior male relations.

As to why the Tyrells are the only ones, I think it’s because everyone else sticks with just stewards and doesn’t see a need to give servants ideas by giving them lofty titles.

My recollection is that Martin lamented the lack of noble titles he initially used in Westeros: virtually everybody’s a lord. If Martin charged you with going back and diversifying the titles of existing characters, how would you go about that ask?

(Throwing two title related questions together for avoidance of repetition.)

I wasn’t able to find GRRM lamenting that – indeed, I think he finds the simplicity of the titles one less thing he has to worry about, like the gender of horses and the width of hips.

But if we were going to start over from scratch, I think I would avoid copying historical systems too closely – baron, count, duke, earl, etc. all have specific cultural meanings that don’t necessarily work in Westerosi contexts.

Rather, I think I’d like to build on existing Westerosi terms and just use them more systematically – so no referring to Ned Stark as “Lord of Winterfell” or “Lord Stark” but rather “Lord Paramount” or “my lord paramount” being the correct form of address – so you’d have Lords Paramount, Lords Principal, Lords Ordinary, and then landed knights and masterly houses (which I would also clear up a bit – if the title of “master” is going to be a recognizably northern thing, there should probably be more than two examples in the series, and I feel like they could have sprinkled in some more masters among the ranks of Robb’s bannermen).

What is the correct use of the honorific “my lord”? We see it used as a general term to refer to anyone socially superior, used uncontroversially to refer to Tyrion and Jaime, but apparently controversial when applied to Edmure before Hoster’s death. What is the correct usage?

The controversy shouldn’t be over Edmure being called “my lord” – that is right and proper as befitting the heir and immiment next Lord Paramount of the Riverlands – but over him being referred to as “Lord Edmure” before the death of Hoster Tully in ASOS.

As you say, “my lord” is used to refer to social superiors as a matter of courtesy, but it’s not a title with legal rights and privileges in the same way that “Lord” is.

All the peerage ranks were originally due to some certain service or position they did that became hereditary titles, but were each of those ranks responsibilities and privledges? I know only that marquess was in charge of marches, aka border lords

Good question!

Since different courts and different languages developed their own system of titles – you don’t get earls outside of Britain or Scandivia, landgrave and freiherr have a very specific Germanic context – it sort of depends on which one you’re looking at.

But there are some etymological roots that can tell us what the original responsibilities of these different titles were (said roles shifted hugely over time):

Duke originates from the Latin dux, and was originally a Roman title indicating the highest-ranking military commander in a given province.
Count comes from the Latin comitem, meaning companion or delegate of the emperor, and was originally a Roman title indicating a high-ranking courtier, and the title continued to have this association with courtly service, see also count palatine, which referred to someone who served in the royal palace. Viscount comes from the Latin vice-comitem, meaning the deputy of a count.
Earl, which is pretty much only used in Britain and Scandinavia, comes from the Anglo-Saxon and means chieftain.
Marquess/Marquis does indeed refer to a lord who holds land on the borders, and thereby has additional responsibilities of defense and fortifications and additional privileges to go along with that.
The etymology of Baron is a bit contested, but is generally held to originally be a military title similar to dux, although indicating a lower rank.