Oldtown is one of the largest cities in Westeros and is by far the oldest, built by the First Men before the Andal Invasion. It survived the invasion by welcoming the Andals, not resisting them. The city is located in the south-west of Westeros, at the mouth of the River Honeywine where it opens onto Whispering Sound and the Sunset Sea beyond.
Oldtown is primarily known as the location of the Citadel, home of the order of Maesters who serve as councillors, doctors, scientists, and postmasters for the Seven Kingdoms. The city's Starry Sept was the seat of the The Faith of the Seven until the construction of the Great Sept of Baelor in King's Landing. Aegon the Conqueror's reign is dated from his entrance into the city of Oldtown and his acknowledgment as King by the High Septon.
Oldtown is also one of the most important ports of the Seven Kingdoms: trading ships from the Summer Islands, the Free Cities, the eastern cities, and the rest of Westeros constantly crowd into its harbors. The city itself is stunningly beautiful; many rivers and canals crisscross its cobbled streets, and breathtaking stone mansions are common. The city lacks the squalor of King's Landing, which usurped its position as the pre-eminent city of Westeros.
The largest structure in the city, and also the tallest structure in Westeros, is the Hightower, a massive [lighthouse] which extends some 800 feet into the sky and is topped by a huge beacon which can be seen for many miles out to sea. Oldtown is ruled from the Hightower by House Hightower. Originally kings in their own right, they later swore fealty to the Gardeners of Highgarden, and later became vassals of the Tyrells after the Conquest. The Hightowers are known for their loyalty and stalwartness. The current ruler of the city is Lord Leyton Hightower.
Oldtown remained aloof from the War of the Five Kings, but late in the war the ironborn under King Euron Greyjoy launched a massive raid along the coast, conquering the Shield Islands and parts of the Arbor before trying to blockade the mouth of the Honeywine. An attempt to attack the city harbour was repulsed by the city's defenders. Oldtown remains under threat from the ironborn.