"Aegon, First of His Name" is the eighth chapter of Conquest & Rebellion: An Animated History of the Seven Kingdoms, a special feature from Game of Thrones: The Complete Seventh Season. It is narrated by Harry Lloyd as Viserys Targaryen.
Viserys Targaryen: The heads of Westeros had bowed to Aegon, but its heart still beat free. Oldtown, the center of the Faith of the Seven. There dwelt the High Septon, the father of the faithful, who commanded the obedience of all Westeros, save the savages of the North and their Old Gods.
When Aegon had landed in Westeros, the High Septon had locked himself in the Starry Sept and fasted for seven days and seven nights, one for each of his gods. All he received for his trouble was the divine wisdom that if Oldtown took up arms against the dragon, the city would burn, faithful and faithless alike.
After the submission of House Stark, Aegon marches towards Oldtown, steeling himself for another battle. But he found the gates open, with the High Septon welcoming him. The pious fool even had the arrogance to grant what Aegon had already won, and anointed the last Valyrian as "Aegon of House Targaryen, First of His Name, King of the Andals and the First Men, Lord of the Seven Kingdoms and Protector of the Realm." As if titles meant anything to a man to whom time itself now bowed. The Maesters would hence divide all history into Before and After Conquest.
Most expected Aegon to stay and make Oldtown his seat, but soon after his coronation, Aegon returned to the mouth of the Blackwater River, where he had first set foot on Westeros. A small town had since sprouted around his primitive fort. To honor their new master, the locals dubbed it "King's Landing," though it looked more fit for a hedge knight, with wooden palisades, muddy streets, and piles of mangled swords carted in from every corner of the conquest.
But when Aegon made it his court, wood became stone, black mud was buried beneath a Red Keep, and the collected swords of Aegon's foes were blasted by dragon fire and became a seat fit for the Conqueror and the greatest dynasty this world has ever known. House Targaryen. My family. My throne. Or so it should have been.
- Oldtown was the largest city in Westeros before King's Landing was constructed, for centuries the seat of the High Septon and leadership of the Faith of the Seven, more or less the cultural heart of Westeros (the seat of the High Septon only moved to King's Landing about a century and a half after the conquest).
- The video says that the Faith of the Seven is the dominant religion in Westeros - everywhere except the North, where the Old Gods still hold sway. Actually, the Iron Islands have their own local religion as well, of the Drowned God. While technically an error, even the books often make this inaccurate statement, focusing on the mainland and forgetting to include the Ironborn off on their remote islands.
- The video says that Aegon was crowned "King of the Andals and the First Men", when in the books the full title is "King of the Andals, the Rhoynar, and the First Men" - including the Rhoynar ancestors of the Dornishmen. Despite being the official title of the monarch who sits on the Iron Throne itself the TV series has been very inconsistent with this title: in Season 1, the official shortened title "King of the Andals and the First Men" was introduced, omitting the Rhoynar, apparently because at the time the showrunners thought that they would never have time to introduce Dorne and didn't want to introduce excess details. From Season 4 onwards, however, the full title from the books has appeared in several episodes, randomly flip-flopping between both versions without explanation (even for the same individual, such as Daenerys Targaryen). The TV writers apparently just stopped keeping track of this.
- As the video points out, King's Landing started out as a ramshackle boomtown that quickly sprouted up around the Targaryens' original military encampment at the mouth of the Blackwater River. In the beginning it was therefore just unpaved muddy streets and wooden palisades: it was quickly built up in the following years, but haphazardly and without much formal "urban planning", leading to the development of several slum districts such as Flea Bottom. When the Targaryens landed there, two years before Aegon was crowned at Oldtown, there was nothing there but a small fishing village and empty hills. Twenty-five years after the Conquest, later in in Aegon I's reign, it had grown larger than White Harbor and Gulltown, to become the third largest city on the continent. Eventually it grew slightly larger than even Oldtown.
- In the year 35 after the Conquest, two years before Aegon I died, he realized that the crude Aegonfort was no proper seat for a king, so he ordered it torn down and construction begun on a grand new royal palace which would become the Red Keep. Aegon I only lived to see the foundations laid, however: it took ten years to finish construction, during the reign of his second son, Maegor the Cruel.
- This video explicitly brings up how Aegon's Conquest was later used by maesters and all others in Westeros as the focal point for their in-universe dating system: dates in the Timeline are reckoned as "Before Conquest" (BC) or "After Conquest" (AC).
- The first novel, coinciding with the events of Season 1 in the TV series, begins in 298 AC: the 298th year After Conqest. Time moves more slowly in the TV series, however, so after that the books and TV series aren't exactly synched up (see "Timeline" for more information).
- This video brings up major implications for Timeline nomenclature in the TV continuity. The first novels actually referred to dates as "AL" for "After Landing" (the first novel is actually in "298 AL"). This reflects how real-life dating systems are inaccurate, however: Aegon always dated his reign from the end of the Conquest, when the High Septon crowned him in Oldtown, not when he first "landed" in Westeros, which took place a full two yearsbefore that at the start of the Conquest. The naming system was always a misnomer. In later books in the series, it appears George R.R. Martin himself wanted to abandon this, and shifted to using the "AC" naming scheme, which is more accurate - with the simple in-universe explanation that the maesters finally managed to argue that this was a better naming scheme. The actual dates didn't change, only the naming system: "298 AL" and "298 AC" refer to the same year.
- Compare this to how in real-life, "10 BC" (Before Christ) and the more modern term "10 BCE" (Before the Common Era) both refer to the same calendar year (and the BC/AD dating system is itself actually inaccurate, due to clerical errors, and Jesus Christ was probably born a couple of years before what was later called "1 AD"). As with the Anno Domini dating system, there is no "year zero" in the After Conquest dating system - it switched from the last day of "1 BC" to the first day of "1 AC".
- Up until now, the TV series has avoided giving dates in dialogue, only on props. Because Martin himself only came up with the shift from "AL" to "AC" after Season 1 of the TV series, however, prop letters in the TV series continued to use the "AL" system. Game of Thrones Wiki therefore continued to list dates using "AL" instead of "AC" (though it's unknown if the TV writers ever even paid attention to the difference). Wikis devoted to the books, meanwhile, such as A Wiki of Ice and Fire, continued to use the "AC" naming system. The mention in this video's dialogue of years being dated "After the Conquest" and not "After the Landing", will be taken as establishing that the "TV continuity" as recorded in this wiki should officially switch from the "AL" to "AC" dating nomenclature for the Timeline.