Between its fantasy action and its more lurid moments, Game of Thrones was a show about intrigue and plotting. Nearly every character had some form of secret they kept and most lied as easily as they breathed. What characters did and didn't know affected not just their own lives, but also the entire continent of Westeros.
Some secrets were relatively minor and didn't have huge consequences. Others, however, were far more wide-ranging. Even if the audience knew the secret, some characters didn't. This saw great suffering for at least some of the cast, often putting entire kingdoms or countries at risk.
10 Littlefinger Was Working With The Lannisters
Following King Robert's death in the first season, a power struggle broke out almost immediately. Ned Stark planned to remove Joffrey and Cersei from power, armed with the knowledge that Joffrey wasn't Robert's son. Ned seemed to be joined by Renly and Littlefinger, other members of the Small Council who claimed to be his allies.
Renly fled when Ned refused to crown him, but Ned was confident to act alongside Littlefinger. This led to the bigger betrayal when the Goldcloaks massacred Ned's men due to Littlefinger actually being Cersei's ally. This caused Ned's execution, the War of the Five Kings, and Joffrey's reign of terror over King's Landing.
9 Casterley Rock Was Broke
Out of any single Great House in Game of Thrones, the Lannisters had a claim to being the most powerful. Aside from their military might and their influence over the Iron Throne, the Lannisters were also the richest house, controlling the most valuable gold mines in all of Westeros.
However, this is revealed to be a lie in season 4 when Tywin Lannister revealed to Cersei that the mines had run dry. With his lifelong focus on increasing House Lannister's power at all cost, Tywin seemed motivated by his penniless state to commit more extreme actions, such as his brutal military campaign in the War of the Five Kings.
8 Rhaegar Married Lyanna With Her Consent
One of the most important parts of Game of Thrones' backstory was Robert's Rebellion, the civil war that took place nineteen years before the first season. The alliances, betrayals, and deaths of the war set up Westeros' political situation by the time of Game of Thrones.
Robert's Rebellion was caused by general discontent towards the brutal rule of Aerys II Targaryen, but the spark that lit the flame involved Lyanna Stark. Rhaegar Targaryen allegedly kidnapped her, and the retaliation from her brother saw events spiral out of control until war broke out. However, Rhaegar never abducted Lyanna and married her with her consent. This means that the devastating war was rooted in a lie.
7 Lysa Arryn Was In Love With Littlefinger
The event that ultimately began Game of Thrones' political struggles was the death of Jon Arryn, the Hand of the King who had kept Westeros intact during Robert's reign. After Arryn's death, Robert had to travel to Westeros and appoint his best friend Ned Stark to the position. This forced Robert to involve himself in King's Landing politics.
Westeros' tensions came to a boil and war broke out within a year, mainly because Ned believed the Lannisters poisoned Arryn. However, his death was actually caused by his wife, Lysa Arryn. Unbeknownst to anyone, she was in love with Littlefinger and was willing to kill her husband on Littlefinger's command.
6 Aerys Targaryen's True Plans
It became clear when Robert's army marched on King's Landing that Aerys II Targaryen had lost Robert's Rebellion, but he refused to surrender, even when his advisors begged him to. This was because, known only to his pyromancers, Aerys planned to wait for the army to reach him. Then, he would burn down the city with Wildfire, rebirthing him as a dragon.
The effects of this secret were huge. Jaime Lannister earned himself a notorious reputation by killing Aerys to stop this, making him a disaffected and lethal Lannister general. Its biggest impacts, however, were felt years later when Cersei used some of the Wildfire to take out the High Septon and solidify her rule over King's Landing.
5 Stannis Baratheon Was Not The Prince Who Was Promised
One of the more enduring candidates in the War of the Five Kings was Stannis Baratheon, Robert's brother and rightful heir to the Iron Throne. He was something of a dark horse, beginning the war with the smallest army and fewest resources. However, the magic of Melisandre aided him. Melisandre believed he was the fabled Prince Who Was Promised and was destined to save the world.
Despite his best efforts, Stannis was killed, proving not to be the subject of prophecy. This secret, unknown to even Stannis and Melisandre, saw thousands die for nothing in Stannis' war, including Stannis' daughter.
4 Ramsay Bolton Being An Utter Monster
House Bolton of the North never had a good reputation, but under the rule of Roose, they were able to pretend to be peaceful and civilized. Despite some ugly rumors, few people knew the depths of the depravity of Ramsay Bolton, Roose's bastard son. Incredibly cruel and evil, Ramsay only enjoyed causing pain and furthering himself.
The consequences of this secret proved bad for the entire North and devastating for two characters in particular. Theon Greyjoy and Sansa Stark spent entire seasons being tormented by Bolton because they didn't know to distrust him. Things only became worse when the Northern lords seemed poised to accept his rule, dooming the North to a monster's tyranny.
3 Robert's Children Were Not His Own
While many secrets in Game of Thrones were a big deal, few were as long-lived or as iconic as the first major revelation. Jaime and Cersei Lannister kept their relationship secret for many years, even as Cersei pretended to have several children with King Robert Baratheon. In reality, all three children were Jaime's.
Even aside from this secret's unpleasant nature, its consequences were devastating. Ultimately, it led to the War of the Five Kings and many deaths. It also proved personally ruinous for many characters, including Ned Stark, Robert, Jon Arryn, Stannis Baratheon, and more.
2 Jon Snow's True Identity As A Targaryen
One of the most enduring mysteries throughout Game of Thrones was Jon Snow's parentage. Allegedly Ned Stark's illegitimate son, his mother remained unknown to the world as a whole. However, in season 6, Jon learned that he was the child of Lyanna Stark and Rhaegar Targaryen and the legitimate heir to the Iron Throne.
This secret, especially when it spread throughout Daenerys' alliance, proved incredibly impactful. It was one of the biggest straws that broke Daenerys' back and turned her into a brutal conquerer, leading to thousands dying in a massacre in King's Landing. Ultimately, this secret led to tragedy for Jon and Daenerys.
1 The Freys And Boltons Plotting With Tywin
Much of Game of Thrones' first three seasons followed Robb Stark as King of the North and the Riverlands, fighting for independence from the Iron Throne. Two of Robb's more significant allies were the Freys and the Boltons. However, both began to hedge their bets in season 3 after several failures. They even began to plot with Tywin Lannister.
In return for pardons and power, the Freys and Boltons arranged to betray Robb Stark. Kept secret until it was far too late, they struck at Edmure Tully's wedding. In the massacre, they butchered Robb Stark, his pregnant wife Talisa, and his mother Catelyn, alongside countless other Northern Lords. It was one of Game of Thrones' most shocking and brutal moments.