The history of the Andals is questionable.

[Lord Stank]

According to the accepted history compiled by both the maesters and the Faith, the Andals are supposed to have invaded Westeros somewhere in the vicinity of 6000 to 5000 years ago. They claim that they fled from the Valyrian freehold which "hungered" for more slaves to mine the Fourteen Flames. But the Valyrian freehold was still in its infancy at that point. They were still fighting wars with the Ghiscari and were centuries away from even establishing Volantis and then eventually fighting the Rhoynar. It does state that the Andals were still in Andalos until the Rhoynish cities fell because they served as a buffer between Valyria and themselves. But it doesn't seem to add up. Not to mention that there are literally no traces of the Faith anywhere in Essos. I mean, they carved seven-pointed stars on the rocks in the Vale which are still seen in the current timeline but left no mark on the land where they claim to have been born. It's difficult to believe that a people who followed a certain religion for what seems to be centuries built no monuments to their faith at all, not even any septs. Also weird that Valyria, which practiced religious tolerance and let a thousand other religions survive, would completely wipe out this one particular religion leaving absolutely no evidence as to its existence anywhere on the continent. It all seems too unlikely to be true.

[The Commentator]

History is subject to erroneous recording, bias, and frail memory. 

[Groo]

2 hours ago, Lord Stank said:

Not to mention that there are literally no traces of the Faith anywhere in Essos.

There's the Sept-Beyond-the-Sea in Braavos that we saw in one of the Arya chapters. The problem is that we didn't really get a look at Pentos since Tyrion was stuck at Illyrio's and we only got a brief look at Volantis. We haven't seen most of the other cities yet. Your basic point is probably still correct but to me that means the original followers of the Faith were probably like the real life Puritans, i.e. kicked out of their original continent so they emigrated across the sea to create their own promised land.

[Lord Lannister]

I think a lot of history in this world is questionable.

[Hugorfonics]

5 hours ago, Lord Lannister said:

I think a lot of history in this world is questionable.

Current events too

[Lord Stank]

10 hours ago, Groo said:

There's the Sept-Beyond-the-Sea in Braavos that we saw in one of the Arya chapters. The problem is that we didn't really get a look at Pentos since Tyrion was stuck at Illyrio's and we only got a brief look at Volantis. We haven't seen most of the other cities yet. Your basic point is probably still correct but to me that means the original followers of the Faith were probably like the real life Puritans, i.e. kicked out of their original continent so they emigrated across the sea to create their own promised land.

The comparison with the Puritans is actually perfect and I hadn't considered that. Although I still have doubts mainly because of Septa Lemore's quote in ADWD I think it was, where she changes out of her septa's robes before they get close to Volantis, saying that the robes would be a dead giveaway that she's from Westeros, implying that there are no practitioners of the Faith on Essos. It could just mean that the few who may exist in Essos don't travel anywhere near Volantis but I think it's more of a hint that the Faith doesn't really have a presence outside Westeros. It is true that we don't know anything about septs existing in other free cities apart from Braavos so I can't really comment on that. And the Sept-Beyond-the-Sea could only have been built at some point after Bravoos announced its existence to the world around 700 years. It was most likely built for the sailors and other travellers coming to Braavos from Westeros so I don't think it can be considered as proof of the Faith surviving in Essos after the migration of the Andals. But yes, I may be reading too much into this whole thing. I just found the history of the Andals in particular to be a little odd based on their claims. 

[The Grey Wolf Strikes Back]

@Lord Stank

I personally see it as a weakness of worldbuilding. (There absolutely should be missionaries in Essos, the North, and beyond the Wall same as there were on the Iron Isles. Furthermore, there absolutely should have been holy wars of some sort to retake Andalos in the aftermath of the Doom.) That being said, one reason why the Andals may have feared Valyrian rule is that the Faith of the Seven is, unlike other Essosi religions, vociferously anti-slavery. In fact, I could easily see the Andals becoming the epicenter of an even larger Faith Militant Uprising if they had stayed.

[Groo]

11 hours ago, Lord Stank said:

The comparison with the Puritans is actually perfect and I hadn't considered that. Although I still have doubts mainly because of Septa Lemore's quote in ADWD I think it was, where she changes out of her septa's robes before they get close to Volantis, saying that the robes would be a dead giveaway that she's from Westeros, implying that there are no practitioners of the Faith on Essos.

Be careful about what she actually said. She wasn't concerned about whether people would think she was Westerosi or not. She was concerned about being recognized. The robes would draw attention and she might be recognized, i.e. she might personally be recognized. That's a point a lot of people gloss over when they start throwing out theories about who Septa Lemore is.

[norwaywolf123]

On 10/28/2021 at 6:25 PM, Lord Stank said:

According to the accepted history compiled by both the maesters and the Faith, the Andals are supposed to have invaded Westeros somewhere in the vicinity of 6000 to 5000 years ago. They claim that they fled from the Valyrian freehold which "hungered" for more slaves to mine the Fourteen Flames. But the Valyrian freehold was still in its infancy at that point. They were still fighting wars with the Ghiscari and were centuries away from even establishing Volantis and then eventually fighting the Rhoynar. It does state that the Andals were still in Andalos until the Rhoynish cities fell because they served as a buffer between Valyria and themselves. But it doesn't seem to add up. Not to mention that there are literally no traces of the Faith anywhere in Essos. I mean, they carved seven-pointed stars on the rocks in the Vale which are still seen in the current timeline but left no mark on the land where they claim to have been born. It's difficult to believe that a people who followed a certain religion for what seems to be centuries built no monuments to their faith at all, not even any septs. Also weird that Valyria, which practiced religious tolerance and let a thousand other religions survive, would completely wipe out this one particular religion leaving absolutely no evidence as to its existence anywhere on the continent. It all seems too unlikely to be true.

The history of Planetos that we are told may contain multiple misinterpretations, lies, transmuted knowledge, etc.