Myrcella Lannister, was born Myrcella Baratheon in 290 AC to King Robert Baratheon and Queen Cersei Lannister. Queen Myrcella was by all accounts a kind girl, providing the comfort to her younger brother Tommen that neither her mother (whom was too focused on her firstborn Joffrey), nor her father (whom was too busy drinking and whoring) nor Joffrey (whom was too busy tormenting) provided. Comme 298 AC amidst the chaos following her fathers death, rumours were spread primarily by Eddard Stark and her uncle, Stannis Baratheon, that Myrcella, along with her siblings, were not the trueborn children of Robert Baratheon but instead bastards made of incest between Cersei Lannister and her twin brother Jaime Lannister. Those who believed these rumours frequently cited that despite previous children of Baratheon-Lannister marriages having black hair, Myrcella had golden hair, like her mother and alleged father. The rumours surrounding her and her siblings parentage along with the execution of Eddard Stark, caused the war of the five kings where Stannis Baratheon, Renly Baratheon, Robb stark and Balon Greyjoy rose up in rebellion against Joffrey Baratheon. The need for allies caused Myrcella's uncle and acting hand of the king Tyrion Lannister to negotiate a marriage between Myrcella and house Martell of Sunspear, the rulers of Dorne. She was then shipped off to Dorne to meet her potential husband. One might have expected this neglect from her parents, the denunciation of her very existence by two of her uncles and being sent to a strange land all at a young age, to have a profound effect on the child. However such an assumption would be wrong. She loved Dorne and its people, even when she was older she made the water gardens a part of the royal demesne. Eventually, her brothers both died, and by all rights she should have been queen then , however her bastard half brother Edric Storm managed to prove he had been legitimised by Tommen and took power in kings landing. By then the marriage with the Martells had gone nowhere, and Myrcella had instead married a distant cousin, Loren Lannister, one of the lannisters of Lannisport. Myrcella lived at court for years and eventually her mother cersei would attack edric whilst he marched north. Edric too died, and her niece and Edric's daughter Rella Baratheon took control. Rella, was angry with Cersei for her "betrayal" and sought to punish her by executing her grandson and Myrcella's at the time only child, Gormon Baratheon, thus causing her to be labelled a kinslayer. Myrcella herself spent months languishing in a dungeon in the reach, until eventually Cersei won the war and freed her. However to everyone's surprise, Cersei did not install Myrcella on the throne as succession should have done, instead she claimed the throne in her own right, arguing she had won it by conquest like Aegon Targaryen and her own husband Robert Baratheon had before her. Myrcella remarried, this time to Gesmund Martell, re-establishing the Lannister-Martell alliance. In 324 AC, Princess Myrcella, now canonised as a Lannister, gave birth to her daughter, Leria Lannister. Many suspect the new princess was not actually the daughter of Gesmund, but was instead the daughter of Ser Garrett Page. If true, and if the rumours surrounding Myrcella's parentage were true, this would be ironic: the throne being inherited by a bastard with a bastard for an heir. Still these were mere rumours. For many years princess Myrcella was the beloved princess of the court, in stark contrast to her feared mother. Many would draw comparisons between Aerys II targaryen "the mad king" and his son Prince Rhaegar Targaryen, who had also been a hated parent with a beloved heir and child. However, there was one main difference between Myrcella Lannister and Rhaegar Targaryen: Myrcella actually lived to be queen of the seven kingdoms, and ascended the throne in 332 AC.
When Myrcella ascended the throne in 332 AC the realm was in chaos. To the north, the starks and Tullys were once again waging a war of independence, to the west the Iron Isles under Iron king Sigfry Greyjoy (the son of Iron King Euron Greyjoy) was still claiming an independent iron isles and raiding the seven kingdoms, and even in the stormlands which were a bastion of Lannister power under lady paramount Tya Lannister, had lost large parts of the south including the powerful castle of Stonehelm, to former pirates loyal to Stannis Baratheon led by Salladhor Saan. Dragonstone had seized independence during the reign of Edric Baratheon, and neither Rella nor Cersei had reconquered it, Rella Baratheon still lived in Lys and there was no reason to think those opposed to house Lannister wouldn't someday rebel to install her on the throne. The situation, though not as bad as the situation her brother Joffrey had inherited, nor her brother Tommen, was still dire.
Luckily Lannister men were in the field. Harrenhal was already in Lannister hands, and Myrcella had only to find self proclaimed king Roland Tully to win the war. Assistance was asked for from Lord Martyn Lannister of Darry, whom was the cousin of Myrcella's mother Cersei, however in a bizarre twist he declared his allegiance to House Stark. The reasons for this are bizarre to say the least, particularly as house lannister and house stark had an intense hatred for one another after the red wedding, and only known to Martyn Lannister. Though it should be noted many river lords particularly house Frey, were positing Martyn as a leader of the riverlands, and considering he was Cersei Lannisters closest male relative aside from her brother husband Jaime, whom was ex kingsguard and thus had a doubtful claim to the throne. It may be argued that Martyn declared his allegiance to house stark because he didn't want to declare allegiance to house tully, and thus declare his claim on the riverlands void, nor house lannister and thus declare his claim to the throne void.
Whatever the case, with his castle taken and many riverlords already disloyal to him, it did not take long to find Roland Tully and he was defeated. Myrcella Lannister decided to spare both his lands and his life. After all, Roland had only risen up because her mother had taken his home, executed his cousin and daughters and declared she wanted his head as well. As someone whose own son had been executed, she completely understood why he had risen up and allowed him to return to Harrenhal after an oath of fealty. However, lord Roland would not survive particularly long. A mere two years after his defeat, lord Willem Frey of riverrun rose up against him, captured him and put him in the dungeons where he died. Some say he took his own life. Others that the Freys, Lannisters, Martyn or even his wife had took his life. Whatever the case, the legitimate male line of house Tully died out. His wife, Jessamyn Tully, born Jessamyn of widow's tower (the ministrels sure had a field day with that) took power in the riverlands.
The north was a different beast. After many years of rule by Jon Stark, and the example he had set by executing Ramsay Bolton, many northerners were loyal to the boy king Edwyn, and his mother Alys Stark. Still the lannisters were in the riverlands, so they immediately put darry to the sword for their treason, and Martyn was taken into custody. The Lannister army then for the second time in history marched north. Moat Cailin had already been secured by Lord Dunstan of hearts home, of white harbour, whom was descended from house Manderly, yet did not adhere to that houses idea of absolute loyalty to house stark and joined the lannisters. Without moat cailin, there was little preventing the armies of the south from taking over the north. Castle after castle fell until eventually house stark gave up.
House stark could not receive the same pardon house Tully had received. Whereas Roland Tully had risen up in desperation and vengeance, house Stark had risen up simply because they believed they could. Whereas house Tully did not hold a grudge because of the red wedding, house Stark did. Whereas Roland Tully was loyal to the gods, lady Alys Stark had no loyalties, being a ruthless greedy woman whom many suspected had assassinated her own brother so that her son could rule in winterfell. Myrcella was a kind woman, she was not a stupid woman, by all accounts often matching her grandfather in intellect. Edwyn Stark was imprisoned in the red keep so as to keep his mother loyal, and Lord Dunstan was raised to warden of the north. In a twist of irony, the new warden of the north, swore an oath of loyalty to house lannister, in much the same way his ancestors the Manderlys had to house Stark.
Martyn was also a different beast. He had proven his disloyalty by declaring war on the crown. Still he was a Lannister, and a much closer relation than any other landed members of the family at that. A compromise was reached. Martyn would be removed from Darry and house Lannister of Darry abolished. The bastard son of a Darry whom had died in the battle of the trident 50 years earlier was made the lord of Darry. Instead Martyn Lannister was made the lord of Highgarden. It is thought that Myrcella placed him there to keep overwatch over warden of the south Lord Arthur Ambrose and other houses in the reach to ensure they stayed loyal, whilst also saying Martyn's ambition by granting him a much stronger castle than Darry, whilst also not allowing for the risk that letting him take the riverlands or the westerlands would entail.
With the separatists dealt with matters in kings landing had to be attended. Of the most import, was Jaime Lannister's new role. The queen's uncle and stepfather was never meant to be a hand of the king, Cersei only put him there because she trusted noone else, and he had no great skill at his job. Instead he was moved to a far more suitable position: master at arms of the realm. His replacement as hand of the king was none other than Gesmund Martell, whom was as known for his intellect as his wife. Critics argued that Myrcella was simply following her mothers example in naming her husband hand of the king. Indeed after Gesmund's death, every single hand of the king was a suspected lover of queen myrcella, with the affair always being suspected before his naming as hand. Jaime, for his part, did not take his demotion as an insult, and served loyally and ably for 8 years until his death in 340 AC.
Also important was queen Myrcella herself. Queen Myrcella as a child had been disfigured in Dorne, her ear cut off by a provocateur attempting to cause a war between Dorne and the lannisters. Many at court wanted her to cover her face with a mask so as to hide this disfigurement. Myrcella refused, many claimed her beauty was immense even with the disfigurement. Ignoring calls to make a mask, Myrcella decided to delve into alchemy, joining the alchemists guild, the first known queen to do so. She built a magnificent laboratory during her reign, compared to her efforts to improve casterly rock yet further. However eventually the laboratory burned down. Still myrclla stayed with the guild until the end of her reign. For her personal banners, Myrcella retained the lion and stag her brothers had used. Some saw it even more fitting for Myrcella to use it than her brothers, after all, Myrcella's claim to the throne came from the fact both her Baratheon father and her Lannister mother had conquered it. Leria Lannister was married off to Leowyn Belmore, by all accounts a genius, though its said he preferred men. Still in 344 AC he granted Leria a son, prince Howard Lannister.
Curiously enough at one point in Myrcella's reign she received a queer message from the archmaester of the citadel. Apparently their citadel in Oldtown had been taken from them, and they wished to establish a new one near Fang Tower. Fang tower was the small Keep of house Clegane, a knightly house sworn to house lannister that was founded by a kennel master whom had been raised to nobility after saving Tytos Lannisters life. The last two members of the house were Gregor Clegane whom had died from the poison of Oberyn Martell's spear following a trial by combat, and Sandor Clegane, whom had disappeared following his desertion from the battle of the blackwater. Myrcella Lannister consented, and allowed the new citadel to be built by this small keep in the westerlands.
To the north, Myrcella's uncle Stannis Baratheon whom had fled their was elected lord commander of the nights watch. This was to be expected, the man having saved it from wildlings decades ago. The news briefly caused panic, before myrcella calmed everyone down. Stannis was an old man, whom had sworn an oath not to interfere in the realm and his only daughter was dead. Some argued that Jon Stark was also a member of the nights watch, yet he reneged on his oaths and destroyed house Bolton, and his daughter and grandson rebelled against the crown. Still ultimately Stannis eventually became the first lord commander since the nights king to have his brothers rebel against him, and he died months after the rebellion (though it should be noted he ruled capably for 14 years).
Domestic affairs dealt with, Myrcella turned to the last remnants of Stannis' rebellion along the coast of the stormlands: pirates. War was declared on Stonehelm, and the lannister armies marched from kings landing and storms end. In the west, houses Crakehall of Crakehall and Lydden of the gold road rebelled against house lannister as well. The armies of the lannisters came down upon Stonehelm and absolutely massacred the pirates there, though it should be noted when the lannisters left to go defeat the rebellion, the pirates actually managed to take Stonehelm itself back (though they no longer had any of the castles loyal to it). This proved an inconvenience when eventually they also took crows nest. However after they did so, a stormlander peasant named Thurgood Seashade gathered an army, overthrew the pirates and swore fealty to house Lannister of Storms End, firmly establishing house Seashade, the lords of Stonehelm and Crows Nest as one of the strongest stormlands houses.
The Crakehalls and Lyddens were absolute fools to rise up. Perhaps they thought they could be the start of a great uprising against house Lannister. Whatever the case they were defeated easily. Myrcella, though as clever as her grandfather, was not nearly as harsh. Instead of wiping out their whole families, They simply had their lands revoked. Crakehall was given to Gewain Hawthorne, and the gold road was restored to Lord Martyn Payne. Fun fact when lord Martyn eventually died, his successor was Podrick Payne, a former squire to Tyrion Lannister.
Half of the pirates and the rebels dealt with, Myrcella turned her attention east, to Dragonstone. Lord Morros Blount of Dragonstone could not really hope to hold out against the Lannisters and eventually bent the knee.
There were still pirates in the stormlands. In addition to Stonehelm, the pirates had also taken Estermont. Myrcella once again marched her armies south, and thoroughly crushed the pirates holding out there, destroying the last remnants of Stannis' kingdom once and for all. Curiously enough, the defeat of the pirates had the odd effect where two islands the pirates also owned known as the skulls and dark den, were annexed into the seven kingdoms, the first expansion of the realm since Dorne swore fealty to house targaryen 200 years ago.
Eventually Lord Beran "the spider" of Butterwell, a Martyn Lannister loyalist, assassinated Jessamyn Tully. The woman left no trueborn heirs, so her bastard son by a summer islander, whom was conceived when Roland was still alive, Edmure Rivers was made lord paramount of the riverlands. He cannonised himself as the trueborn son of Roland Tully, which legally restored House Tully, though in practice, only a fool would look at Edmure's dark skin and conclude his father was a Tully. Not everyone supported the reborn house Tully, least of all the Freys whom rebelled to install Martyn Lannister in Harrenhal. The lannister armies once more marched north, and though more formidable than every previous enemy save house Stark, the freys and their allies were still defeated.
The last major opposition to House Lannister in westeros came from the ironborn. For years they had raided, raped and pillaged as they pleased, their civilisation good for nothing else. It was finally time for queen myrcella to act. Every fleet she could gather was gathered, every soldier raised. The greyjoys attempted a preemptive strike on kings landing, only to be easily beaten by the garrison. With their army defeated in the second battle of the blackwater, the ironborn had no options but to bend the knee. At last all loose ends caused by the war of the five kings had been taken care of.
In 346 AC something curious happened. Raella Redwyne, called by many "the mountain that rides" due to her similar size to the aforementioned Gregor Clegane whom had the same nickname, raised an army of sellswords, stormed the reach, and took Lord Alyn Ambrose and lord Martyn Lannister hostage. She then declared herself lady paramount of the reach and kicked martyn lannister out of highgarden and moved in herself. Funnily enough her brother had been lord commander of the kingsguard only two years earlier (when he died). The brother of the first mountain that rides was also a member of the kingsguard.
One of the last acts of Myrcella's reign was to attempt to smooth things over with the Starks. She offered to send money to pay reparations for the red wedding. However Alys Stark wouldn't have it, arguing that not only were reparations not enough but if Myrcella was truly changed she would release Edwyn. Edwyn, now a grown man, was similarly spiteful. Though at face value the Stark's points had merit, it should be noted Myrcella herself had nothing to do with the red wedding, that being the brainchild of her grandfather Tywin, during the reign of her brother Joffrey. One could argue that Myrcella was being the bigger woman by trying to smooth things over despite herself having done no wrong. Still whatever the case, house Stark refused her generosity, and Edwyn remained in the dungeon.
In 347 AC after 15 years of ruling wisely and squashing rebellion and insurgency, Myrcella Lannister passed away peacefully in her sleep. She was 57 years old. She was succeeded by queen Leria Lannister.
