In the Enchanted Forest, there were five kingdoms: Breton, Gaul, Germania, Hispania, and Wendland.
Centuries ago, a Breton warrior, Vortigern, made a bid for becoming the high king of the entire forest. By his side, were mercenaries from both the Scots of DunBroch and Germania, as he murdered his king and took over the kingdom.
But, Vortigern soon lost control of his mercenaries who murdered several Breton nobles, keep him around only as a puppet king, and ravaged the countryside of Breton, raiding several villages, including one belonging to a young woman named Nimue.
Nimue, along with fellow survivors of the raids, allied with the great wizard, Merlin, to fight against Vortigern's mercenaries. He helped her by bringing her to the Holy Grail, which provided her with immortality and magic, allowing her to destroy Vortigern and his mercenaries.
So, it was that the legitimate royal line of Breton returned to power and the kingdom began its rebuilding process.
However, Merlin realized that the power and lust for vengeance was corrupting Nimue's soul when she began taking the title, 'The Dark One', so he created a dagger tied to her soul to keep her under control. But, one of Nimue's followers pounced on him in his attempt to take control of her, allowing Nimue to seal him inside of a tree, where he remains to this day.
Nimue's follower decided to take power, so he then stabbed Nimue in the heart with the dagger, killing her. But, though Nimue's physical body died, her soul remained in the dagger, allowing her to possess the soul of her killer, starting the chain of Dark Ones.
The Dark One chain went on, with Nimue becoming more and more powerful with every soul that she inhabited. Eventually, a Wendlandian noble took possession of the dagger, forcing the then-current Dark One, Zoso, under his will, including drafting villagers for the Ogre Wars.
One such village lived Rumplestiltskin, a crippled wool seller, and his son, Baelfire.
Rumple had lived a harsh life: he lost his mother in infancy, his father, a con man named Malcolm, abandoned him to regain his lost youth on the island of Neverland, wool spinsters took him in after his father left him (which is where he acquired his skill at spinning wool), married a woman named Milah to live in a Wendlandian village as wool spinners, was drafted to serve in an Ogre War, but, fearing for his pregnant wife back home, decided to desert (by injuring himself, giving himself a limp in the process) only to come home to a wife (and kingdom) who despised him for his new reputation as a coward who fled the field of battle, and a son to take care of.
Then, Milah, who took to drinking away her sorrow in the local bar, disappeared, with Rumple and his son fearing her kidnapped, raped, and murdered by a pirate named Killian Jones.
Rumple was aghast when he learned that the Wendlandian nobility had resorted to drafting children to fight in the latest Ogre War. Fearing for his son's life, Rumple complained of his predicament to a man he met in the bar.
Unknown to him, this man was Zoso, the Dark One. Seeing his chance to be free, Zoso told Rumple of how the local Duke has a dagger that can control the Dark One, suggesting that Rumple steal the dagger to take control of the Dark One. Rumple agreed, so he sneaked into the Duke's castle and stole the dagger.
Using the dagger, Rumple summoned the Dark One, and, in a moment of panic, stabbed him with the dagger. As he approached the dying figure, he was shocked to discover that it was his new friend under the mask and that, by killing Zoso, he became the new Dark One. Infused with the Dark One's powers, when soldiers came to draft Bae in the morning, Rumple slaughtered them all, though this left Bae terrified of his father's new personality.
Rumple then used his magic to kill all the Ogres on the battlefields, bringing the Ogre War to a close. He led the children back to the village, who now considered him to be a hero, his reputation as a coward now forgotten.
Out of all her hosts, Nimue found Rumple to be the most intriguing due to him being a doting father. But, this overprotectiveness of Bae allowed the darkness in his soul to corrupt him, turning him into a tyrant that wanted to keep Bae under his control at all times and punishing anyone who harmed Bae, even accidentally, with death.
One morning, Rumple awoke to find Bae gone, along with the rest of the boys in their village. He went to investigate and found it to be the work of a masked piper playing a magic flute. He unmasked the piper only to be shocked to find that it was his father, now known as Peter Pan, who has taken up kidnapping children to serve him on the island as his 'Lost Boys'. Rumple whisked Bae and the rest of the boys from their village, but he never forgot about his father's threat to take Bae away from him.
Bae continued to tire of the villagers fearing him due to his father, so Rumple decided to make a deal with his son: if Bae can find a way for Rumple to give up the Dark One powers without dying, he would do it. The next day, Bae came home with a magic bean (given to him by the Blue Fairy), which can take them to a land without magic, which would allow Rumple to live without magic.
Alarmed, Nimue influenced Rumple to not go into the portal with Bae, leaving him alone and with a mission: to find this land without magic and to reunite with his son.
For a century, Rumple took on a trickster persona which made deals with anyone willing to trust him, with horrific consequences for any foolish enough to break a deal with him.
On one deal, he discovered that, not only was Milah still alive, but she had joined Jones' crew as his lover. Enraged at her for leaving him and Bae, he used magic to grab her heart out of her chest and crush it to dust, killing her. Her lover tried to attack Rumple only to get his hand chopped off, but was spared due to Rumple wanting him to live in misery. The now-named Captain Hook went to Neverland, where he believed he would live long enough to find a way to kill Rumple. There, he met Peter Pan, who hired him to get items, such as food, for him and the Lost Boys.
As time went on, Rumple realized that the only way for Bae to not have died from old age at this point was if he was on Neverland. This meant that if Rumple wanted to get his son back, he would have to face his father, and that meant he would need to recruit help.
He found his chance when he met Cora, the miller's daughter in Hispania, making a deal with her that, if he helps her spin straw into gold, she will give him her first-born child. He also decided to teach her how to use magic, having bonded with her due to both having experienced humiliation at the hands of nobility. Though her spinning straw into gold won Cora Prince Henry's hand, Rumple, who had fallen in love with her during the lessons, was left disappointed when she chose to marry the prince instead of run away with him, so that they could raise her child together.
Around this time, the kingdoms were each in different struggles. King George of Wendland and his wife were struggling to have a child, as the Queen had been secretly cursed with an infertility potion by a rival noblewoman bitter at her for being the one to marry the king. King Leopold and Queen Eva of Germania were also having trouble conceiving. King Xavier of Hispania was struggling with his kingdom's finances until Princess Cora's gold filled its coffers.
King Uther of Breton died without a male heir (only a bastard son, a toddler named Arthur, fostered by a knight, Sir Ector). Due to his marriage to Uther's daughter, Leah, Duke Stefan took the throne. However, after his coronation, the spirit of Merlin appeared before the young king and told him that the warrior who will take the sword, Excalibur, from the stone will be the true one to inherit Breton and, one day, become high king of the entire Enchanted Forest.
Amazed by the prophecy, Stefan tried to pull the sword out himself only to be disappointed when it did not budge. He decided to accept that he was not Uther's true heir and steel himself to abdicate once the warrior Merlin mentioned came along to pull Excalibur from the stone.