Then, during the feast/tournament, some random Knight – the Knight of the Laughing Tree – challenged the squires who bulled Howland Reed and won. No one knows who TF this knight really was, but some people say it was Lyanna Stark in disguise (I guess Arya Stark isn’t the only badass in the Stark family).
Rhaegar’s father – the Mad King – found out about this powerful knight and got all bent out of shape over him and decided someone needed to kill him – so, he sent his son Rhaegar to kill him. Theories state that Rhaegar found out that the knight was Lyanna and the two fell madly in love. We – of course – are unsure.
But, at the tournament, Rhaegar won the entire thing and instead of crowning his wife queen – he went and crowned Lyanna Stark the “queen of love and beauty.” Can you even imagine your husband straight up going “nah” and moving onto another woman right in front of you?!?
So – of course, everyone was shocked because people knew Lyanna and Robbie B were supposed to get married and – Rhaegar was already married. But he was all – f*ck that, I want Lyanna. The two ended up running away together.
Now – the Stark family was pissed TF off because Lyanna was being rebellious and, of course, they blamed Rhaegar for “kidnapping her.” So, Brandon Stark (not Bran, his uncle) rode to King’s Landing and told Aerys II that he wanted Rhaegar dead for kidnapping his little sister.
But The Mad King plays no games, so he arrested Brandon, called their father (Ned’s father) Rickard Stark and executed them both brutally in the Throne Room in front of everyone (which is something Jon Snow brought up in episode three when he met Dany for the first time, how her father murdered his uncle and grandfather).
So – this is how Robert’s Rebellion began against the Mad King. Robbie B was hella close with the Stark family and, Aerys II demanded Robbie B and Ned be killed from his hand, Jon Arryn. At the same time, Ned married Cat Tully and Jon Arryn married Cat’s sister, Lysa – so that Jon Arryn would protect the Stark family rather than murder them all.
Then – Robert and Rhaegar met in a battle between the two of them – almost like Battle of the Bastards but just one-on-one. Robert ended up murdering Rhaegar because, you don’t steal a man’s woman – I guess.
Now, the Lannisters hadn’t played a big role in any of this for the entirety thus far, until, The Mad King sent his sister-wife to Dragonstone with baby Dany in her belly for protection. But, he didn’t let Rhaegar’s wife – Elia – or their two kids leave King’s Landing. But, all of the sudden, Tywin Lannister appeared out of thin air, bent the knee to The Mad King and said he would obey the king. Instead, he sacked the city like the savage he was. The Mountain – who Oberyn fought on King’s Landing – raped Elia and murdered both of her children, before killing her, too.
So, Rhaegar lost his wife and two children that day and Oberyn lost his sister. Which, was why, when he fought The Mountain at King’s Landing – he kept repeating “you raped her, you murdered her, you killed her children.”
Then – Ned Stark comes to King’s Landing like “where TF is my brother and father” and sees that the Lannisters have taken over and Jamie is on the Iron Throne – after slaying the King. King Slayer.
This is where Bran’s vision in season six comes into play – Ned was angry at the death and murder of Elia and her two children, but Robert was hyped because Rhaegar had stolen his girl. So, Ned was like “Bye Felicia” and went to Dorne, looking for his sister.
He ends up being stopped by the Targaryen kingsguard, who was protecting someone – aka Lyanna Stark and her baby – aka Rhaegar’s baby. Even though Rhaegar and his father were both murdered already – Jon was born and he was now the rightful heir to the Targaryen throne.
In the vision Bran had – Lyanna ends up dying after giving birth to Jon and asks Ned to protect him and not tell Robert – because he’d be so angry that he’d kill the baby. So, Ned takes one for the team and pretends he had a bastard child instead of Lyanna having a baby with Rhaegar. Talk about a great brother.
After this, Robert took the Iron Throne, Dany was born in Dragonstone and smuggled with her “only remaining family member” Viserys to Braavos and – then we meet them when Viserys trades Dany to the Dothraki.
This means, Jon Snow aka Targaryen is really Dany’s nephew, even though he is older than she is – because, he was born before Dany yet, is her brother’s son. He is also somewhat Stark blood, since he was Lyanna’s son – therefore, still holds some allegiance to Winterfell. But, seeing as he’s Rhaegar’s son, he may be the actual heir to the Iron Throne and not Dany.
Now, Dany and Jon are all lovey dovey lately and it’s annoying AF – but, when Jon finds out and Dany finds out – because Bran will spill the beans eventually – it can either be great for them or horrible. Dany is a super powerful broad now and she’s not about sharing the throne. And, if she finds out Jon is legit the heir and she’s not – she’ll be angry. But, Jon really doesn’t have an interest in being king – so maybe it won’t be so bad after all? We’ll have to wait and see.