My main character is one of 5 deities that make up the "Terram faith" The country she resides in is a theocracy of that faith; with a king and queen appointed by high priests and priestesses. The issue I'm having is usually in theocracies people with other beliefs were at risk of persecution etc. & that doesn't align with her character. How could a theocracy work if they are tolerant of people worshipping outside of the ruling religion?
First, as already covered in this answer, a theocracy can be more concerned with people following its rules than with people following its god. Historically some Muslim rulers were like that, such as the caliphs in al-Andalus (modern-day Spain) in the 10th-11th centuries.
Second, your religion(s) might practice monolatry or henotheism rather than monotheism. That is, they might accept the existence of other gods (and thus their worshippers), while considering them inferior to The One Important God (your deity character). Examples of such religions from our world include Zoroastrianism, Hellenism, (some?) Hinduism, ancient Egyptian religions (where the pharaohs are gods but not the only gods), and other religions of the Ancient Near East.
Third, your religions might hold that different gods rule different geographic areas. Your deity is the local one and most important in that place, but maybe some of the people living there came from elsewhere and maintain family traditions connected to their original gods. So long as they're not interfering with the dominant theocrats, that might be fine. Your theocrats might even see them as charity work -- we have to help those poor people who haven't yet come over to (insert your deity here).
It seems like the main issue wouldn't be people who practice other religions. It would be people who refuse to follow the rules of the theocratic religion.
It's likely that there would be many laws in that nation that someone who didn't adhere to that religion would disagree with. If someone came to that country and refused to follow those laws, and was punished for it, would you consider that to be an instance of being intolerant of people worshiping outside the ruling religion? (And, perhaps more to the point: would other people in that setting consider it intolerant? Would the person being punished consider it intolerant?)
As an example, imagine if they had dietary laws that were actual political laws. Would it be intolerant to send someone to prison for eating bacon? Because that seems like the sort of thing that might happen in a setting like this.
(I'm ignoring the degenerate case where there's officially a state religion but in name only, such as the Church of England.)
Certainly you could write such a theocracy. Judaism is believed to only pertain to people who are ethnically Jews. A Jewish theocracy would not attempt to compel people of other ethnicities to convert.
The kingdom could view religion as tied to heritage and expect foreigners who move into the kingdom to practice the religion of the foreigner's homeland. For that matter, many early polytheistic faiths had this point of view. A Roman would not think it odd for an Parthian to worship the Parthian gods. They often allowed conquered people to worship their own gods.
This works even better if ancestor worship is an aspect of the religion. In many African tribes, for example, part of the reason for practicing religion was to honor the ancestors who had passed down those beliefs.
We have examples of theocracied both in real life and fiction, in which the ruler is appointed by priests, and which are accepting of other cultures and faiths.
In real life, the Tibet is ruled by the Dalai Lama, and the Vatican is ruled by the pope. As for the latter, say what you will about catholics, but the vatican has been spreading a message about peace and love for quite some time now.
In fiction, Aang from the Avatar series lived in a theocracy under the rulle of an abbot. That is based on real life Tibet.
I have heard the Mongols described this way—I have my doubts about that characterization being historically accurate, but it is plausible so even if the Mongols weren’t actually, your people could be.
Basically, the description I have heard is that the Mongols believed that the spirits of their homelands demanded conquest from them, which they did. They conquered far and wide, and never made any attempt to convert anybody—the spirits they followed were intrinsically tied to the places they came from. People who had never been there couldn’t worship them and it wouldn’t make any sense for them to try. Instead, it was assumed they would just go on worshiping the spirits of their own places—which were no threat to the Mongols’ spirits, obviously, seeing as the Mongols conquered the place to begin with.
So consider the possibility of a ruling class that is a theocracy, but for theological reasons has absolutely zero concern about what the non-ruling classes do or do not worship. In fact, the non-ruling classes may well be considered ineligible for worshiping the ruling class’s god(s), and attempts to do so may be seen as sacrilege and/or treason.
Consider the Ottoman Empire as an historical example. Despite being a Muslim empire ruled with fairly stringent religious conditions, they permitted Jews and Christians to consider practising their faiths -- the status of "People of the Book" denoted that they were seen as similar enough to Islam to be allowed to exist.
While they were allowed to exist, they had other restrictions on them: the Patriarch of Constantinople, for instance, now had to be approved by the Sultan after his nomination; and non-Muslims were subject to an additional tax because of their faith. This is likely how religious plurality would be expressed in a fictional theocracy.
The United Kingdom is an example of a modern day theocracy. Queen Elizabeth II is the head of the Anglican church:
The British monarch has the constitutional title of Supreme Governor of the Church of England. The canon law of the Church of England states, "We acknowledge that the Queen's most excellent Majesty, acting according to the laws of the realm, is the highest power under God in this kingdom, and has supreme authority over all persons in all causes, as well ecclesiastical as civil."
I daresay that the UK doesn't persecute anybody who does not follow their particular branch of christianity. This would be an example of rulers just not caring all that much about what religion their subjects practice.
In a different, more historical perspective, Muslim countries were generally tolerant of People of the Book. Anyone who was considered 'of the book' but not muslim was given specific rights and duties, and generally allowed to practice their religion in relative peace:
Dhimmi is a historical term referring to the status accorded to People of the Book living in an Islamic state. The word literally means "protected person." According to scholars, dhimmis had their rights fully protected in their communities, but as citizens in the Islamic state, had certain restrictions, and it was obligatory for them to pay the jizya tax, which complemented the zakat, or alms, paid by the Muslim subjects. Dhimmis were excluded from specific duties assigned to Muslims, and did not enjoy certain political rights reserved for Muslims, but were otherwise equal under the laws of property, contract, and obligation.
So, how might you use this in your world? As others have suggested, you could have the rulers simply not care about what the plebeian masses believe. Alternatively, you could have your rulers be tolerant of anyone who practices the Terram Faith, whether their specific version of the religion matches that of the ruler or not.
Look at the history of both religious and political liberty in Europe.
First there were the Catholic church and the pope, who would at least in theory have to confirm rulers.
Then there was the principle that the ruler set the branch of christianity that was permissible, cuius regio, eius religio.
After some bloody wars, there was the Peace of Westphalia which, among other things, allowed christians to believe and practice other branches of christianity.
This did not yet abolish the role of bishops as temporal rulers, e.g. in Electorate of Trier, which only happened by the Napoleonic wars.
The religious Electorates were no clear-cut example of a theocracy because their rulers "wore two hats," so to speak, but you can look at them as a pattern.
Certain nations consisted primarily of people persecuted for their faith, thus making them less eager to persecute others in the same way. Examples of this to various extents are for example the united states and the Netherlands.
Because the Netherlands had ceded from Spain over both political and religious issues, it practiced certain forms of tolerance towards people of certain other religions and opened its borders for religious dissenters (Protestants and Jews) from elsewhere, while maintaining its persecution and later discrimination against native Catholics. Descartes for instance lived in the Netherlands for most of his adult life.
Source: Wikipedia article about History of Religion in the Netherlands
I picked the above quote specifically because it also highlights that this freedom wasn't in any way absolute. Especially Catholicism had it hard in certain parts of the Netherlands - the parts that were hurt most under the Spanish catholic persecution - , but at the same time it was primarily "just" discrimination. Anyway, the end result was a society which created a culture of "do whatever you want as long as it doesn't affect others and isn't too different morally". What was "too" different was a bit flexible though, but as far as my limited knowledge goes atheists, Jews, Muslims and most of the different Christian denominations had it fairly "well", but Catholics and some of the more extreme "Christian" sects had it harder. Although the Dutch traded a lot with the far east I have no idea how Asian religions were treated in the Netherlands as I think few people traveled from those parts to Europe.
Anyway, leaving the history of our world aside, from a world building point of view this is an easy motivation you can give a nation to be comparatively tolerant towards other religions and it also allows you to balance how far this will go. If your MC is a deity of flowers and there is another deity of plainness that is all about trampling all flowers in the world then it's going to be incredibly hard to justify that those would live together, but as long as the "let us both do our own thing as long as we don't interfere with each other" can be upheld it's quite possible to have a strong theocracy which still welcomes other religions.
A small but relevant historical example:
During the First Crusade, one Crusader army decided that, hey, why go all the way to Jerusalem to kill armed Muslims when we have defenseless Jews right here? Which is described in this video as the first large-scale antisemitic pogrom of Europe.
Which the Catholic Church apparently really, really didn't like. To the point that some bishops - which, having temporal powers, were basically local theocratic lords - went to great lengths to try and protect their Jewish populations, including military action.
So yes, a theocracy can indeed be tolerant of other faiths, and go pretty far to defend said tolerance.
You should take a look at the questionable burdens of leadership of a troll emperor. This is an example of a successful theocracy with freedom of religion.
This works because the ruling deity is actually a real god, and as they would put it, their divinity does not depend on whether people believe they are god; whether people believe or not, they will continue to exist and be divine regardless. As a result of their divinity being a clear brute fact, their people tend to just accept them as a fact of life. If anyone was to try and worship a different god, they would be allowed to, but consider to be a little bit strange; maybe even mentally unstable. Like people in our world believing the earth is flat - there's no law against believing in, but it's a bit weird.
Since your question suggests the gods in your world area also real, you can quite easily just make it a background fact that they are the only ones worshipped. Like how google is the only search engine most people use - yes, hypothetically askjeeves might be around somewhere, but it doesn't matter; people don't 'askjeeves' things, they 'google' them. So in your world, people don't 'pray to zeus', they just 'pray'. The 'to zeus' but is taken for granted, because who else would they be praying to? Thor? Oh yeah, I heard he's one of those gods those weird foreigners worship...
TL;DR: People of other faiths only get persecuted if those faiths are equally valid. If heretics get struck by lightning, there will very quickly not be any heretics left. No need to break out the toches and pitchforks when you can just sit back and watch the show.
The answer to this question differs between "true" theocracies where the religious leaders are also the secular leaders and theocracies which just legitimizte the secular leaders.
A "true" theocracy, like the historical Muslim Iqta‘ system where the religious leaders were also the secular leaders, can actually get around with not everyone following them. Their power comes from their armies, not their moral authority. They don't care if people believe in them, because those who do not believe that it is God's will that they follow the Caliph can be convinced by force.
On the other hand, a theocracy which just legitimizes the kings or queens but doesn't wield any direct power, like the Catholic church in the medieval age for example, is much more dependent on faith. Their whole authority is derived from the fact that the majority of the population believes in them. When they are no longer the majority religion, the church no longer has the authority to appoint rulers. Also, the rulers have no longer a reason to seek the approval from the church, because the majority of their underlings wouldn't care about the opinion of the church anyway.
For example, consider the following scenario:
The king gets into an argument with the priests. So the king declares that he decided to convert to a different religion. The priests have no power over him anymore. He tells his guards (who aren't Terram faithful) to throw the priests out of the castle. How would the Terram priesthood react to this situation?
The first reaction would likely be to declare that the king is no longer the king and that they appointed a new one. But then what? How do they put their new king in power when the old one controls the army? Tell the peasants that the king is no longer the king, that they should to take up arms, slay the heathen and enforce the divine right of the new king? Good luck with that if most peasants have a completely different religion and thus no reason to listen to the Terram church at all.
So if you want a theocracy with true power, either put it in control of the peasants or put it in control of the army.
One thing you could try which wasn't (afaik) ever done in real-world history would be a combination of theocracy and military shadow-dictatorship. Put the priesthood in control of the army. Have them turn all soldiers into religious fanatics. Let the soldiers swear allegiance to the gods and their priests, not to the king. Now even the king doesn't need to be all that religious, because if he ever acts up against the will of the priests, his own soldiers will turn against him.
Similarly to other answers, I think the main solution surrounds what, exactly, your theocracy stands for. However, the other answers gloss over the heart of the matter, which is what, exactly, you mean by 'tolerance', and what the goals of your theocracy are.
TLDR: Your theocracy must stand for some set of beliefs that no one (or almost no one) in the kingdom is actually willing to disagree with - it'd probably be best if it's something that isn't even taught, or codified, but just how things are. It can then proclaim tolerance by not caring about anything anyone believes, so long as it doesn't contradict those unspoken base beliefs. It will look tolerant, so long as most people don't disagree with its core principles. To be tolerant of disagreement with your core principles, however, is to show that those aren't actually your core principles.
At some level, I strongly submit that every person has a set of beliefs that they believe are true for them, but not necessarily something that others should be forced to follow, and also a set of beliefs that they consider universal, that can't be compromised on, and that others should be compelled to adhere to. I will define the first set of things as "disagreements a person is willing to be tolerant of", and the second set as "disagreements a person is not willing to tolerant of". There is always something in that second set.
For most of the west, I think that core moral belief can be boiled down to "don't hurt innocent people", and/or "try to make everyone who matters to you happy". People proclaim tolerance towards anyone who follows those principles, and generally refuses to tolerate any actions that go contrary to them. There aren't really any cries for 'tolerance' towards people who thinks beating their spouse is OK, regardless of whether or not the spouse complains. Nor does anyone proclaim tolerance for people who think murder is OK, or rape, or animal abuse. Most tolerance, is merely the state of holding moral views whose core beliefs don't conflict. The only way a person, being, or government, can truly tolerate everyone, is if they don't believe any actions to be fundamentally wrong, and worth preventing or fighting against. Therefore, your deity's tolerance must be limited.
At some level, if two people have beliefs, and those beliefs contradict, then each person must decide whether or not the issue is important enough to try to force the other person to change their behavior.
Tolerance is saying "this isn't important enough to force".
*Perhaps you could get around this with a religion that expressly disbelieves in the concept of 'right' and 'wrong'. Not moral relativism, but the actual absence of those concepts. If you take that path, I'd advise avoiding contact with anything your reader might feel strongly about. The rest of this answer ignores theocracies that don't believe in the concepts of right and wrong.
If you want a theocracy that can proclaim tolerance, then, you'll have to make the things it really cares about something that most people never interact with, or are at least all willing to submit to, and that doesn't touch the things people could actually disagree with.
Note, however, that tolerance can only be proclaimed by contrast - it isn't "tolerance" to let people do things you don't care about. It's only tolerance if you're letting people doing things you disagree with. Your theocracy therefore needs to assert two classes of beliefs: one that it doesn't really care whether the people believe or not, which it can claim to be tolerant about, and another (possibly hidden) that it does care about, which doesn't really impact anyone.
You may find the concept of doublethink necessary.
Other answers brought up conquering nations that allowed their subjects to continue practicing whatever they wanted. That's an example of a group being 'tolerant' about things they don't care enough about to force, so long as the subjects do the thing the conquerors actually care about - paying tribute, or not taking up arms against them, etc.
The best way to make your theocracy reign while having freedom of religion is to consider your religion to not be a religion. If you treat your religion as a proven fact, and define religions as beliefs contrary to or alongside the truth that is your god(s), you make it into a matter of accepting the truth. In this way, you relegate other religions to a conspiracy theory, an unproven or untrue belief.
If your religion is actually not a religion, and religions are actually just fake news, you can easily have freedom of religion. You have no state sponsored religion, so the priests are just state workers, who are responsible for appeasing the god(s). You can set up religious freedom as a first amendment right.
If you want to go even farther, you might want to see this question about limiting religion. The question asks how to limit religion in the society, and there are some really interesting answers there. You can actually exclude followers of any other religion from becoming a leader on the basis of freedom of religion. Political leaders are undoubtedly influenced by religion, which makes them a puppet of their gods and religious leaders. In your state it is necessary to have leaders with no religious ties so the leader focuses on the common good.
You can use the above point to get rid of anyone the religion doesn't like. All that you have to do is spread rumors that the candidate was observed praying to a false god. Then you launch a fake investigation, conclude that the candidate was in fact lying about their religious affiliations, and throw them in jail for collusion. You can get rid of leaders in other religions in this way too. Just claim that they tried to manipulate a candidate and you can lock them up too.
The Druze still do not permit conversion, either away from or to their religion. Marriage outside the Druze faith is rare and is strongly discouraged. Many Druze religious practices are kept secret, even from the community as a whole. Only an elite of initiates, known as ʿuqqāl (“knowers”), participate fully in their religious services and have access to the secret teachings of the scriptures...
Neither Druze nor Zoroastrianism accept converts, you have to be born to a worshiper in order to join (in the case of Zoroastrianism, both parents must be members). It might be possible for your theocracy to be similar - they run the country and perhaps a large amount of the population is of the same faith, but foreigners cannot join. They neither hate nor disparage those of other faiths.
Prior to the Age of Enlightenment, cuius regio, eius religio (whose realm, his religion; meaning "I'm the boss, you worship my way") was the predominant view. If the Monarch was a Catholic, you better convert. The first treaty to change that was the Augsburg Settlement. This treaty allowed for a modest freedom of religion in the Holy Roman Empire, now you have both kinds: Catholic and Lutheran. A later treaty, ending the Thirty Years War allowed for more choices and created the major principles behind "what is a country", international justice and order. Perhaps your world has had similar wars of religion settled by treaties.
The kind of theocracy you’re thinking of is a country ruled by priests, with “a king and queen appointed by high priests and priestesses.” That kind of government can easily tolerate things like people worshiping on a different day of the week, celebrating different holidays, or following different family laws.
Although the Abrahamic religions teach that it is morally wrong to practice “idolatry,” the religions of East and South Asia traditionally don’t, and you might take inspiration from the relationship between priests and rulers in Hinduism or Buddhism.
Some things that might test the limits of tolerance, even there:
Brigham Young hired nuns and priests to set up schools in Salt Lake. While Utah was not legally a theocracy, in fact the elders of the church had a lot of say in government. Salt Lake had almost as many Roman Catholics as Mormons at one pont.
I went to school for a semester at Brigham Young University in Provo. Provo is 95+% Mormon. (In a city of 100,000 people there are two churches -- one catholic, one methodist that aren't mormon) The influence of the church is such that there are no restaurants, only a few drug stores and one grocery store open on Sunday. I didn't drive, so I don't recall about gas stations.
If one religion dominates in numbers, then there customs will affect the entire culture.
It can but probably won't.
All"-cracies" are political entities. The basis of politics is to maximise one's own influence, while minimising that of competitors. Religious institutions, especially political ones, only peacefully coexist when:
Your realm is different from real world theocracies in that your deity is actually present and active.
Governments generally become oppressive when they feel threatened. Rulers backed by a active deity has very little to feel threatened by, unless another deity is trying to take over.
The ruling class will come from the priesthood of the deity in control. As long as people of other religions accept that, they can worship whoever they want.
There is likely to be some friction. The ruling religion will have some rules of conduct. Breaking these rules IN PUBLIC might be considered indecent behaviour, even if the person follow another religion. In private things should be more relaxed.
Again, a ruling deity can decide what they want. They can choose to say "Beards are icky, I don't want to see them on anyone." OR they can choose to say "MY followers should shave, but others can do what they want." Either way, the priesthood will have to go along.