The Doom occurs in 114BC, as previously stated, Starting the Century of Blood/Bleeding Years on Essos where the Remnant City States of the Freehold devolve into a massive civil war, as the Dothraki Hordes come out of the East, we know that Sarnor, Essaria and most the northernmost Ghiscari Kingdom are utterly destroyed by the dothraki, as presumably their armies were too depleted to put up any defense against the Idiot Hordes.
One of the Last Dragon Riders, I believe he was Prince of Qohor, outside of Dragonstone dies in the magical fires of the Doom, seeking to reclaim the vast wealths of Valyria.
King Tommen II Lannister, attempts to sail and reclaim Brightroar from the ruins as the sword was apparently being serviced in Valyria, neither he nor his ships are ever seen again. Starting a three century obssession among the Rock-dwellers to get it back, or get another sword for themselves.
In essence this state continues until about 5 Before Conquest, when Volantis, Greatest of the Valyrian Remnant States, finally gets enough of an upper hand to threaten Tyrosh, Tyrosh's main trade partner is the Kingdom of the Stormlands, Ruled by Argillac Durrandon Last Son of Durran Godsgrief doesn't take kindly to this disruption and sends military aid, Aegon Targaryen also sends aid, now Aegon's idea is that he'll use Argillac as his main Military Hammer and Ally in taking Westeros, and so offers Argillac his bastard brother, Orys Baratheon, in Marriage to Argillac's daughter Argella.
Argillac refuses the match.
Aegon appears to accept the situation, until 3 years later when he descends, quite literally onto Westeros in a tide of Fire and Blood.
Orys slays Argillac in single-combat taking the Stormlands, Argella, and the Colours and Words of House Durrandon for his own, as First Lord Paramount of House Baratheon.
And so in the end of the Conquest acouple years later, we come to what we know as thuroughly documented history.
Edit: Informational bit.
The Interesting bit, about where we are set to arrive is that the Arbor is quite small, but with a larger population then many other places, now the interesting thing here, is that this largish population, is nearly never actually on the island.
Most of the Island is covered in vast Vineyards and Forests, feeding the urbanised population centers and tradehubs that are, including but not exclusively set as, Ryamsport, Vinetown and Starfish Harbor.
The majority of those who call the island home however are sailors, crewing the over 1200 ships that call the Arbor, home. Now the Redwyne Fleet, largest among its kind in the Seven Kingdoms numbers 200 wargalleys. The other 1000 plus ships are Merchantmen of all flavours, there's also a substantial Whaling fleet.
So out of the many people who live on the Arbor, not alot of them actually live daily on the Arbor.
Now adding 25k to that might seem like a drop in the bucket, but then it's not due to the fairly small size of the bloody island.
The Arbor at best estimate is 197 miles long by 90 miles wide, or 320km long by 145km wide, contrasting this with a more familiar territory to the Numenoreans, say Andustar Province on Numenor, Andustar was 175 miles/281km from the peninsulae to the border with Mittalmar, and some 150 miles/242km wide counting from Eldalondë to the northern coast. The Arbor is comparable in size to Orrostar.
So the Arbor is a hotter, dryer 1/5th of Numenor in size. With a massive population of religious zealots north across the waters.
On the plus side, the majority of it's population is a massive merchant class, that would probably have little to compunction in ousting the ruling Redwynes from power if there's at least acouple of barrels of gold in it for them.
/joke
