In Song Dynasty China, there was one woman who started life as a common prostitute and street performer. By the end of her life, she had ruled as Empress of China. Her regnal name is Empress Zhangxian Mingsu, but she is more commonly known as Empress Liu.

(I'll be adapting my answer here from a post on my website about her and two of the other concubines of Emperor Zhenzong.)

Lady Liu began her life in obscurity. Orphaned as a child, she first came to the attention of history when she gained a reputation as an excellent hand drum player and singer. The official histories of the Song Dynasty later attempted to give her a more respectable origin story, but she was probably a prostitute. A silversmith named Gong Mei was her owner or procurer, so when he was low on money, he came upon the idea of selling her to the palace. Other accounts say that Prince Zhao Yuanxiu, the future Emperor Zhenzong, had heard that Gong Mei knew beautiful women from Sichuan and wanted to see one for himself. Either way, in the year 983, Liu was brought to the capital of Kaifeng and introduced to the prince. The two were both teenagers, just a year apart in age, and the prince fell madly in love with her. Her beauty and musical skills are said to have instantly enchanted him.

Not everyone in the prince's household was pleased with his new paramour. His wet nurse was a woman who still held great sway in the palace. When Emperor Taizong asked why his son had become so thin and listless, the prince's wet nurse was quick to blame Lady Liu. Chinese medicine taught that too much sex would drain a man of his energy. Aside from this, the wet nurse was displeased that the prince was giving so much attention to a woman from such a lowly background. After all, entertainers were considered to be of such a debased social status that it was legally impossible for them to marry respectable commoners, let alone the Son of Heaven. Taizong accepted the wet nurse's judgement and ordered Liu to be expelled from the palace.

But the prince had other plans. He secretly paid an official to build an extra wing in his house to keep Liu. And for fourteen years, that is where she stayed. It wasn't until 997 that Taizong died and the prince ascended to the throne as Emperor Zhenzong. Only then was Liu welcome back into the palace. Zhenzong had an official empress, Empress Guo, but Liu was his true love. When Guo died in 1007, Zhenzong wanted to immediately install Liu as empress, but his advisors offered great resistance. Proper empresses were from prominent families in good standing with the empire, not orphans who'd worked as musicians and prostitutes. "Because she had risen from poor and lowly origins," they said, "she could not be mother of the world." But in 1012, he finally got his wish, and Liu was made his official imperial wife.

A very important woman in Liu's story is the woman known as Consort Yang. Yang's father and grandfather were both military officials, which was the normal rank for women who entered into palace service - much more respectable than Liu's background as a prostitute entertainer. Palace service meant working in one of the six palace bureaus, and becoming available to the emperor as a concubine. Of course, the bureaus employed hundreds, even thousands of women, so very few of them ever came to the Emperor's attention.

Yang entered the palace one year before Zhenzong became emperor, at the age of 13. Liu took an immediate liking to Yang and soon took the teenager under her wing. Every time Zhenzong promoted Liu to a higher rank of consort, she convinced him to promote Yang at the same time. The concubines were ranked just like the palace women and court officials. When Zhenzong promoted Liu, he promoted Yang to one rank below her. By the time Liu was made empress in 1012, Yang was second only to her. Liu's high esteem of Yang would be a recurring theme throughout her career in the palace.

As much as Zhenzong was enamoured with Liu, there was one thing she couldn't provide him: an heir. In the decades since they'd first fallen in love, Liu had given birth to no children. He had no surviving children from Empress Guo either, and so he turned to the wider pool of palace women available to him to seek an heir. It was a maid called Lady Li who finally gave birth to Zhenzong's son Prince Zhouyi, the future Emperor Renzong. At this time, Liu had not yet been made Zhenzong's official empress, but as One of Cultivated Countenance, she held a much higher rank than Lady Li. Because of this, there was nothing Li could do when Zhenzong's favourite concubine came to her and demanded her son be handed over to be raised by Liu instead.

And who was Liu's crucial ally in this bold political move? Consort Yang. Liu's temper was feared throughout the palace, so everyone was too afraid to go against her wishes. And so Liu adopted Prince Shouyi, pushing Li into a life in the shadows of the palace, unable to claim her own son. Yang, for her part, was said by later historians to be very wise in her decision to support Liu. Rather than getting in the way of the tempestuous Liu by pursuing her own ambitions, she secured her own position at court by remaining loyal to the woman who was said to love her dearly.

As the prince grew up, no one dared tell him that Li was his birth mother. Instead, Liu and Yang raised the boy together. Aside from raising the prince, Liu became deeply involved in the administration of the empire. Around the year 1020, Emperor Zhenzong fell very ill. When he became too weak to rule the government on his own, he turned to Liu to run it for him. Although she came from a poor background, she had studied voraciously since coming to his harem, no doubt taking advantage of the education system offered to girls training for palace service. Consequently, by the time Zhenzong became ill, she was well-versed in politics and history as well as being considered a capable manager of the inner palace's affairs. She became the main point of contact for government ministers and issued decisions in Zhenzong's name. Although this was Zhenzong's will, his male ministers were not happy that Liu was being given so much power. They resented her for being a woman and for being low-born. They also were unhappy at how she gave positions to her "family": Once Liu had entered the palace as an imperial consort, she adopted her former patron Gong Mei as her brother. He changed his surname to Liu, and she began bestowing official honours on members of his family. In previous dynasties, aspiring empresses had built up power bases of their own kin to help them overcome the objections of male court officials. Since Liu had no family of her own, she had to make one.

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There are many examples of this across many world monarchies. However, so far I have not seen any other users give any examples from medieval or early modern Western Europe, of which there are several. The most unusual may be the morganatic marriage of King Eric and Queen Karin of Sweden, a reflection of the uniquely dramatic and chaotic situation of the Swedish court in the middle 16th century.

Karin Månsdotter was queen of Sweden for about 6 months, from July 1568 to January 1569. Prior to this, she was simply a teenage servant in the king's court. Like many women and girls employed throughout history, Karin entered or was coerced into a sexual relationship with her older and more powerful employer, King Eric XIV of Sweden. Very unusually however, Eric and Karin chose to sanctify their relationship through marriage.

There were two big reasons for this. First, King Eric suffered from a mental illness caused bouts of rage which not only trouble the court but caused severe instability among the nobility. In one notorious instance, he ordered the arrest of five noblemen on dubious charges of disloyalty. According to historian Gary Dean Peterson, King Eric made the shocking choice of personally killing at least some of these men, stabbing them to death in their prison cells. This act, and the broader crisis of Eric's violent temperament, was a huge crisis for the Swedish monarchy. Favored courtier Jöran Persson sought to assuage the king's mental illness by connecting him with somebody who could calm his violent tendencies, preferably a spouse or a mistress.

An additional matter was that Eric's instability made him a weak and unpopular monarch among the nobility, particularly given that his execution of suspected traitors was popularly perceived of as a mass murder. Eric and his advisor Persson feared that marrying into a Swedish noble family or even foreign royalty would allow his new in-laws to dominate the court and harm the standing of both Eric and Persson. According to Sture Arnell's book on Queen Karin, after she became Eric's mistress, Persson identified the teenage Karin as a potential moderating influence on the unmarried 30-something king, and thought that this low-born servant could serve as an effective liason between the court and the nobles and the unstable king.

Eric and Karin initially married in secret, through a morganatic contract that would not guarantee inheritance rights to their children. But after a year, potentially due Karin's successes at calming the king, the two had a second, conventional marriage and the servant Karin was crowned Queen of Sweden.

This is not exactly a fairy tale story, as it involves a powerful violent man marrying a younger woman whose age and station makes her consent dubious in the situation. Accordingly, it does not have a fairy tale ending. Months after the second wedding and coronation, a group of nobles including Eric's own brothers rebelled against him. Eric was overthrown and the royal family, now including two small children, was held captive in a Finnish castle. They remained imprisoned for about a decade, and after several years of confinement together and the birth of two children, Eric was put into solitary confinement to prevent the birth of more children that could harm the claim of the usurper King Johan III. He died alone in 1577, upon which Karin and their children were freed but lived the rest of their lives in relative obscurity as members of the lower nobility.

In Austria, there was Anna Plochl. Anna was the daughter of the the postmaster in Bad Aussee, a small town in the Austrian region of Styria. By the age of 15, Anna's mother had died and she was responsible for managing her family's household. That was also the age when she first met Austrian Archduke Johann, when they were both at Lake Toplitz.

Brother of emperor Franz I, Johann was a bit of a relative free-thinker before he met Anna. Intended by his family for the military, Johann preferred nature, technology and agriculture, which he pursued even while off in military engagements during the Napoleonic wars. He also collected minerals, and engaged in early alpinism (mountain climbing) and hunting.

While remaining loyal to the court and his brother the emperor, Johann complained that the concerns of ordinary people were too often ignored, and himself engaged in multiple social and economic projects meant to improve society and living standards. He had the idea of creating a national, Austrian, identity, to unite the empire, but the court did not support it, a failure that drove Johann further into his own interests.

Once the Napoleonic wars were over, and Johann was free to pursue more projects. He returned to his regional travels, and so met Anna on the banks of the Toplitzsee in 1819.

According to the story, the local staff was a person short to drive Johann's carriage to the next post station. The postmaster's daughter Anna could do it, so she was disguised as a boy and presented as such. Johann saw through the disguise and was impressed with the bold and vivacious Anna. He told her who he was, and promised to write her. Anna did not believe either of those claims, until the letters arrived, and shortly thereafter, the visiting Archduke himself.

The two quickly began some sort of relationship, first by writing and then with visits. Both faced family opposition. Anna's father understandably worried that his teenage daughter could be swept up into becoming a royal mistress, only to be later discarded. He wanted her to marry a local man who would offer her a more stable and respected future.

On the other side, Johann's brother, Emperor Franz I, preferred his brother in more politicly useful locations than rural Styria, and planned a politically advantageous match for Johann. A postmaster's daughter from a small town in the mountains was a handicap on the global stage, not an advantage. Meanwhile, at home, the powerful Prince Metternich warned Emperor Franz I that marriage to a local girl would make Johann even more popular within Austria, causing a negative comparison to the emperor himself.

By 1823, Johann declared that wanted to marry Anna, but his brother the emperor refused the required permission. Johann was too loyal to do it anyway, but he was equally unwilling to live without Anna. Instead, Anna and Johann proceeded as if they were married.

Forbidden from coming to Vienna, Anna moved into Johann's residence in Voralberg, where Johann had a wheel factory. While Johann travelled to Vienna and engaged in other Archdukely duties, Anna ran his businesses in Voralberg, and did a good enough job that within a year she was also running Brandhof Castle, Johann's model estate. Anna was also well known for her culinary ability, and many dishes are attributed to her to this day - some of which she even actually did cook.

Still, they officially remained unmarried and Anna could not accompany Johann when his obligations called him from their country homes. Finally, after six years, in 1829, the emperor appears to have given up on waiting Anna out, and gave permissions so that they could marry. Perhaps he was worried about illegitimate children, or had just had sympathy for his brother's demonstrated love, but he was not fully accepting of the marriage itself. Although the permission to marry was granted, the permission to announce that they were married did not come until 1833.

If illegitimate children were the fear, Kaiser Franz did not have to worry - Anna and Johann had one child, a son named Franz after his imperial uncle, born in 1839.

The imperial family also got some political advantages from this marriage, if not the ones Franz I sought. Coming after the Napoleonic wars, Anna's imperial romance drew attention to Johann's social efforts and the legend surrounding their love story, most famously portrayed by the artist Matthäus Loder, was a useful means of retaining loyalty in a time of growing nationalism and dissent.

After the revolution of 1848, Johann was elected head of government by the National Assembly. He was a compromise candidate everyone could agree on, and Anna was a part of that.

Throughout their lives, Anna and Johann maintained a strong base in Styria and ran multiple technological, economic and social projects. Johann was even mayor of a local town, Stainz. After his death, Anna continued their work in Styria, particularly the social projects.

Both of them, but especially Anna, remain important local figures and the subjects of much legend today. A movie was made about them in 2006, and Anna is a major figure in regional tourism.

Their single child, Franz von Meran, is the ancestor of many alive today, including the aristocraticly named Karl-Theodor Maria Nikolaus Johann Jacob Philipp Franz Joseph Sylvester Buhl-Freiherr von und zu Guttenberg, aka the former secretary general of Germany's ruling CDU party, and economics and then defense minister, between 2008 and 2011.

Karl-Theodor is a lobbyist now. Following his parents' divorce, his mother married Adolf Henkell-von Ribbentrop, named after that Adolf, son of that von Ribbentropp. Karl-Therodor himself is married to a Bismark. But that is the problem once we get too close to our modern time - we can see the warts, too. Still, the legend remains.

There was a monarchy that made relationships with commoners a national policy. And some of those relationships were a turned into a tales.. I can guess you can call them fairy tales, once you accept that your Cinderella is much older, cunning and experienced in intrigues that make Game of the Thrones look like Disney movie.

I'm talking about Ottoman Sultanate.When you look at the wikipedia bios for sultans the "spouse" link below the image is conspicuously absent, replaced by much more humble "concubine" up to Suleiman the Magnificent

Up to his reign Sultans harem simply lacked the queen, the top spouse. Ottomas were no strangers to altar diplomacy but by XV century next lineage of the ruling house was born by the concubines- lots of whom were enslaved girls brought from slave markets- carefully checked by eunuchs and female members of the house they got a shot into Sultan's bed. The birth of the child secured their position for a while at least- when the son came of age she was supposed to follow him to province he was supposed to govern. Then when the Sultan died they witnessed their sons run with all their supporters to the capital to fight for their life in The Battle Royale (kardeş katliamı) that lest only the next Sultan alive.To prevent infighting and favoritism Sultans were expected to cease intimate contact with concubine after birth of the son.

Enter Roxolena. The legend says that she was a daugther of the priest. One of the few things we can say for sure is that she wasn't one of the famous Circassian beauties- she came from modern day Poland/Ukraine. By the time we can say anything for sure she was free woman, Mehmed's legal spouse with brand new title of Halseki Sultan, living in Topkapi palace, sending diplomatic letters to Poland and managing his husband's affairs when he was away. She bore him 5 sons, but unfortunately didn;t live long enough to secure their throne, making herself Valide Sultan- mother of the Sultan, the most important woman with unquestionable authority.

The later shifts in inheritance made a title of Halseki Sultan obsolete and it was abolished by the late XVII century- but Valide Sultans managed to hold their power up to the end of the sultanate itself.

Abbott, Elizabeth . Mistresses: A History of the Other Woman. Overlook. ISBN 978-1-59020-876-2.

Dr Galina I Yermolenko (2013). Roxolana in European Literature, History and Culturea. Ashgate Publishing, Ltd. p. 275. ISBN 978-1-409-47611-5.