TL;DR - Arthur Dayne+Lyanna=Jon Snow. Arthur Dayne is a KG and sworn to celibacy. Rhaegar, his BFF, courted Lyanna on his behalf, Cyrano de Bergerac style. Jon Snow, will become The Sword of the Morning, and wield Dawn, which is Lightbringer. (cross posted from westeros.org) So my idea goes something like this: In light of the the fact that the the crown at the tourney was a garland of blue winter roses, (which is extremely strange and ominous considering the identity of the recipient) What if Jon's father was not Rhaegar, but someone very close to Rhaegar?
"The Red Keep had its secrets too. Even Rhaegar. The Prince of Dragonstone had never trusted him as he had trusted Arthur Dayne. Harrenhal was proof of that. The year of the false spring." - Barristan, ADwD
"They found the Golden Company beside the river as the sun was lowering in the west. It was a camp that even Arthur Dayne might have approved of-" Jon Connington, ADwD
"Young Lord Connington was dear to the prince as well, but **his oldest friend was Arthur Dayne.** - Daenerys, ASOS
There is a clear picture emerging here that no one was closer to Rhaegar than Arthur Dayne. What if the year of the false spring was EXACTLY that: a deception? What if we are witnessing a darkly twisted Cyrano de Bergerac style farce, which lead ultimately to ruin and death and war? It would fit in nicely with GRRM's dark romanticism, I think. So, essentially, we have Rhaegar courting Lyanna on Arthur Dayne's behalf, whom as a Knight of the Kingsguard is sworn to celibacy, the consequences of which cause the whole Targaryen regime to go belly up?
"The Dragon Prince sang a song so sad it made the wolf maid sniffle" - Bran, ASOS
Rhaegar sang the song, but what if someone else wrote it? Perhaps Arthur Dayne? If Stannis wields a false Lightbringer, and Mel's visions show her only "Snow," does that not imply that Jon will wield the true Lightbringer? This fits nicely with Elio and Linda's theory that Dawn is Lightbringer, If Jon is Arthur Dayne's son, and therefore the Sword of the Morning.There seems to be a strong connection between the Daynes, grief, tragedy, regret and sadness. This is emblematized by Ashara Dayne being the most prominent example of suicide in the story.
"Ashara's daughter had been stillborn, and his fair lady had thrown herself from a tower soon after, mad with grief for the child she had lost, and perhaps for the man who had dishonored her at Harrenhal as well. She died never knowing that Barristan had loved her. How could she? He was a knight of the Kingsguard, sworn to celibacy. No good could have come from telling her his feelings. No good came from silence either. If I had unhorsed Rhaegar and crowned Ashara Queen of Love and Beauty, might she have looked to me instead of Stark? He would never know. But of all his failures, none haunted Barristan Selmy so much as that." - Barristan, ADwD
Here we have both a linkage between Daynes and sorrow, and a Knight of the Kingsguard ruminating on his vow of Celibacy. Hmm. Interesting.
"'Why is it that my cousin is the only Dayne anyone remembers?'
'He was a great knight,' Ser Arys Oakheart put in. 'He had a great sword,' Darkstar said. 'And a great heart,'" -Arianne, AFFC
"'We all swore oaths,' said Arthur Dayne, so sadly." - Jaime, ASOS
Oaths of celibacy?
'The finest knight I ever saw was Ser Arthur Dayne, who fought with a blade called Dawn, forged from the heart of a fallen star. They called him the Sword of the Morning, and he would of killed me but for Howland Reed.' Father had gotten sad then, and he would say no more." - Bran, ACoK
"...their faces burned clear, even now. Ser Arthur Dayne, the Sword of the Morning, had a sad smile on his lips."
'And now it begins,' said Ser Arthur Dayne, the Sword of the Morning. He unsheathed Dawn and held it with both hands. The blade was pale as milkglass, alive with light. 'No,' Ned said, with sadness in his voice. 'Now it ends.' As they came together in a rush of steel and shadow, he could hear Lyanna screaming. 'Eddard!' she called. A storm of rose petals blew across a blood-streaked sky, as blue as the eyes of death. - Eddard, AGoT
Is she screaming because her brother and her lover are about fight each other to the death?