system
Given the following post, respond as if you're commenting on Reddit:
human
[ASOIAF/GOT] Has Westeros ever had to deal with attacks by slavers from the East?

I always assumed that slavers never bothered attacking Westeros because doing so meant incurring the wrath of an entire continent.  They are clearly willing to attack smaller nations however, given their conflicts with the Summer Isles. And the less maritime/martial the nation is, the more slavers it has to deal with (e.g Naath). 

But the Seven Kingdoms weren't always united. Did slavers ever attack the old kingdoms of the First Men? The Ironborn were able to completely and utterly spank the North for a long while, simply because they were a more martial culture with more boats;  I don't see any reason why Eastern slavers couldn't have done the same, if they were willing to make the trip.

Was Westeros simply too far for the trip to be worth it? Slavery is forbidden by the Faith of the Seven, but I can't remember the Old Gods having anything to say about it. Did the First Men ever take and sell slaves?

Did the Valyrians ever raid Westeros for slaves?

Essentially, did chattel slavery ever have a presence on Westeros? Was Westeros ever part of the global slave marketplace?
gpt
It was probably raided a few times, but as you point out it was a long way to go.

It's also worth considering the geography of Westeros. The slavers come from the south coast of Essos, which means they're coming at Westeros from the south-east. The easiest part of the continent to approach is therefore the south coast of Dorne, which is rocky and inhospitable and therefore sparsely populated. Finding enough slaves to be worth the trip without attacking a major settlement is going to be time-consuming.

You could sail further west, but that's a long way to go. If you're going that far, Naath is closer and, provided you make your visit brief, far more profitable.

Or you could sail north, but that involves going through the Stepstones - a notorious haunt of pirates. And you'd have to sail back through them to get home, which means the pirates you managed to sneak past on your way north will be waiting for you in force when you return south with your ships slowed by their cargoes of slaves.