History Main / HeirInLaw

* In ''Manga/DrStone'', the position of Village Chief is gained by winning a fighting tournament and then marrying the Village Priestess, who is always the daughter of the chief and previous priestess. This is important in the early part of the manga, as the strongest warrior in the village, Magma, is a {{Jerkass}} who doesn't care for the current priestess, [[IllGirl Ruri]] and just wanted the throne. This motivates the various members of the Kingdom of Science, most of whom are close to Ruri, to join the tournmanent in order to save her. [[spoiler: In the end, Senku wins but immediately divorces her, both for the sake of Chrome, who he knows loves her, and because [[CelibateHero he doesn't want to be married]], though he still becomes village chief after curing her pneumonia.]]

** Souma is given the throne directly by Albert, but he is still engaged to Liscia, the princess, to give the abdication more legitimacy. Souma later also takes over Amidonia and again gets legitimacy by marrying the Roroa, princess of that country.
** After being driven out of his country, Julius Amidonia marries the princess of the Kingdom of Lastania, and he's set to become the next king rather than Tia Lastania taking the throne. It's unclear if this is because the monarch has to be male or Tia just doesn't want to rule.

* This is [[spoiler:initially]] the case for Princess Yumina Urnea Belfast in ''LightNovel/InAnotherWorldWithMySmartphone''. (A male cousin would've been higher in the line of succession, but Yumina only had a single female cousin.) As such, her parents are eager to push her into an ArrangedMarriage with main protagonist Mochizuki Touya after he foils an assassination plot on the King's life (and passes a SecretTestOfCharacter via Yumina's [[MagicEye Mystical Eyes]]). Touya is initially hesitant about marrying Yumina, but she eventually grows on him ([[MarryThemAll as do his other eventual fiancées]]), but he has no interest in ruling the Kingdom of Belfast. [[spoiler:Later in the light novels, this last point is subverted twice, as the King and Queen of Belfast eventually have a son to take over as the Crown Prince, while Touya himself becomes the ruler of a small Duchy that's established for him.]]

* [[PlayingWithATrope Played with]] several times in ''LightNovel/HowARealistHeroRebuiltTheKingdom'':
** Before the story starts, Albert becomes king of Elfrieden because he married the [[SuccessionCrisis only surviving member of the royal family]]. His wife, Elisha, could take the throne, but the royal family is so controversial that putting someone else on the throne is safest.
** Souma is given the throne directly by Albert, but he is still engaged to Liscia, the princess, to give the abdication more legitimacy. Souma later also takes over Amidonia and again gets legitimacy by marrying the Roroa, princess of that country.
** After being driven out of his country, Julius Amidonia marries the princess of the Kingdom of Lastania, and he's set to become the next king rather than Tia Lastania taking the throne. It's unclear if this is because the monarch has to be male or Tia just doesn't want to rule.

* In a vaguely postumous example, the pagan (or possibly Orthodox) Didysis Kunigaikštis (Grand Duke) [[https://en.wikipedia.org/wiki/W%C5%82adys%C5%82aw_II_Jagie%C5%82%C5%82o Jogaila Algirdaitis of Lithuania]] was baptized into the Catholic Church as Władysław at age 24 (minimum) to Królowa [[SheIsTheKing (King)]] [[https://en.wikipedia.org/wiki/Jadwiga_of_Poland Jadwiga Andegaweńska]] (who was [[AChildShallLeadThem 12, max]]) and ruled Poland for the rest of his life. outliving both Jadwiga who [[DeathByChildbirth survived her only child by mere days]] but the latter's second cousin (a fellow great grand-child of Polish King [[https://en.wikipedia.org/wiki/W%C5%82adys%C5%82aw_I_%C5%81okietek Władysław I Łokietek]]) and ''her'' offspring. It was wife number four Sofja[=/=]/Sonka, born to the Ruthenized Lithuanian house of Alšėniškiai/Гальшанскі, from whom the Jagiellonian dynasty traces their decent.

* In [[Myth/ClassicalMythology Greek mythology]], Menelaus, prince of Mycenae, becomes king of Sparta through marriage to princess Helen after her stepfather and brothers die. Thus he also had a political motive for [[UsefulNotes/TheTrojanWar getting Helen back]], since she was the justification for his own position.

** This is most likely why Holy Roman Emperor UsefulNotes/{{Charlemagne}} never let his daughters marry; he feared their husbands might challenge him or his sons one day for the throne. It had happened to other rulers from his line, so it was a reasonable fear.
*** He was, however, fine with them having long-term relationships with his courtiers and even children with said courtiers, since neither the lovers nor their sons could claim the throne without the benefit of marriage.

** A downplayed example in the case of The Tudor claim to the throne of England and France; the Tudors already had their own claim to the throne, as descendants of the House of Lancaster, but it was weak. Henry VII's marriage to Elizabeth of York (heiress to the previous royal lineage) as well as the marriage by Princess Katherine of France (widow of Henry V) to Owen Tudor (Henry's grandfather) helped strengthen their claim, though it was primarily enforced by [[AppealToForce right of conquest]].

** This is most likely why Holy Roman Emperor Charlemagne never let his daughters marry; he feared their husbands might challenge him or his sons one day for the throne. It had happened to other rulers from his line, so it was a reasonable fear.

** This is most likely why Eleanor, the Fair Maid of Brittany, was kept imprisoned for entire life; after the death of her brother, Arthur, she was technically the rightful heiress to the Plantagenets' vast holdings and a potential husband might have tried to press her claim.

** William III became King of England through his marriage to Mary II, initially as co-monarch rather than sole monarch. However, he continued to rule after her death rather than make way for her heirs, as he would have done had he just been a consort. It probably helped that William was also the next male in the line of succession as Mary's [[KissingCousins first cousin]], and that he took the throne in what was essentially a coup d'etat (Parliament basically issued him a very polite engraved invitation to come and "invade" the country, as they didn't like his father-in-law King James II setting up a Catholic dynasty).

* This was a sore spot between [[MaryOfScotland Mary Queen of Scots]] and her husband, Henry Stuart, Lord Darnley. While Darnley was officially the King of Scotland, with his name coming before Mary's on government documents and his face appearing on coinage, she was the queen and he the consort. Darnley was constantly badgering Mary and the Scottish Parliament to bestow him with the Crown Matrimonial, which would have allowed him to inherit the throne and rule in his own right if Mary died. Darnley's ambition to rule Scotland in place of his wife was enough that Catherine de Medici, Queen Mother of France, wondered if it affected his feelings toward his and Mary's son, whose claim to the succession trumped his.

** William III became King of England through his marriage to Mary II, initially as co-monarch rather than sole monarch. However, he continued to rule after her death rather than make way for her heirs, as he would have done had he just been a consort. It probably helped that William was also the next male in the line of succession as Mary's [[KissingCousins first cousin]], and that he took the throne in what was essentially a coup d'etat (Parliament basically issued him a very polite engraved invitation to come and "invade" the country, because Britain).
*** At the same time, it was made clear his children would only succeed if they were also ''Mary's'' children; if they failed to have children or their children predeceased them (which they did), the throne would (and eventually did) pass to Mary's sister, Anne, even if William had remarried and had children by another wife (though he never did), because Anne would have still been considered higher in the succession (as Mary's sister)than any child of William's by another woman (who would be her first cousins-once-removed).
** Downplayed example in the case of The Tudor claim to the throne of England and France; the Tudors already had their own claim to the throne, as descendants of the House of Lancaster, but it was weak. Henry VII's marriage to Elizabeth of York (heiress to the previous royal lineage) as well as the marriage by Princess Katherine of France (widow of Henry V) to Owen Tudor (Henry's grandfather) helped strengthen their claim, though it was primarily enforced by [[AppealToForce right of conquest]].

** This is most likely why Eleanor, the Fair Maid of Brittany was kept imprisoned for entire life; after the death of her brother, Arthur, she was technically the rightful heiress to the Plantagenets' vast holdings and a potential husband might have tried to press her claim.

* In ''VideoGame/AlQadimTheGeniesCurse'', the Caliph's daughter is due to marry a son of the Al-Hazrad family (you, the protagonist). However, the Al-Hazrads' genie nearly drowns the Caliph in a storm, and he decides that his soon-to-be in-laws aren't content with just securing the marriage — they want the him out of the way so that they seize the throne. The Caliph accepts that the you were ignorant of the plot yourself, since you helped rescue him, but the other Al-Hazrads are imprisoned.

* In ''Manga/DrStone'', the position of Village Chief is gained by winning a fighting tournament and then marrying the Village Priestess, who is always the daughter of the chief and previous maiden. This is important in the early part of the manga, as the strongest warrior in the village, Magma, is a {{Jerkass}} who doesn't care for the current priestess, [[IllGirl Ruri]] and just wanted the throne. This motivates the various members of the Kingdom of Science, most of whom are close to Ruri, to join the tournmanent in order to save her. [[spoiler: In the end, Senku wins but immediately divorces her, both for the sake of Chrome, who he knows loves her, and because [[CelibateHero he doesn't want to be married]], though he still becomes village chief after curing her pneumonia.]]

* The entire plot of ''Kingdom River'' is driven by this. Queen Joan of the Middle Kingdom has only one child, Princess Rachel, who is more interested in books and learning than ruling a kingdom. Because of this, various River lords want to marry her to get to the throne. Joan wants to find a son-in-law who will be strong enough to hold the throne and keep the lords in check, but who's also patient enough to wait for the throne, rather than kill her to get to it immediately and who will actually care about her daughter, rather than kill or abandon her once they have the throne. For this reason, she reluctantly allies with the protagonist Sam Monroe, Captain-General of North Mexico, against their common enemy, Toghrul Khan, hoping he'll fulfill that need. [[spoiler: the book ends with Sam marrying Rachel and becoming king after Joan dies in battle.]]

* The ''Literature/{{Deverry}}'' books feature a case where, upon the death of a king, his three mutually antagonistic sons-in-law make bids for power. They stop short of proclaiming themselves kings, but do advance claims to be regent for the "rightful" king, their own respective sons (the old king's grandsons).

* This is the plan in ''Literature/TheHorseAndHisBoy''. A Calormene prince wants to marry Queen Susan of Narnia so he'll be able to take over the country.

** Odette and Derek's whole [[ArrangedMarriage betrothal]] is basically a double version of this, as their parents want to combine their two kingdoms.

* In ''WesternAnimation/{{Shrek}}'', Lord Farquaad wanted to marry Princess Fiona solely because it would make him a king. When he discovers Fiona's curse, he plans to keep her locked away and never be seen again. Unfortunately for him, his reign doesn't last too long before he becomes dragon food.

* In ''WesternAnimation/{{Shrek}}'', Lord Farquaad wanted to marry Princess Fiona solely because it would make him a king. When he discovers about Fiona's curse, he plans to keep her locked away and never be seen again. Unfortunately for him, his reign doesn't last too long before he becomes dragon food.

* In ''Manga/VisionOfEscaflowne'', the king of Asturia has three daughters and no sons. The eldest, Marlene, is deceased and the second, Eries, refuses to marry. As such, the throne is expected to pass to the husband of the third princess, Millerna, who is currently unmarried. Oddly enough, the eldest princess was actually married with a son before her death but neither of them seem to be considered for the throne, presumably because she married the ruler of another country.

* Discussed in ''VideoGame/JadeEmpire''; Silk Fox fears that Death's Hand will try to convicne her father to invoke this trope on her. [[spoiler: she's wrong, for a number of reasons.]]

* ''VideoGame/YesYourGrace'': Succession works that way in the game's setting. At some point, it's explictly stated that since the PlayerCharacter doesn't have a son, the next-in-line for his throne is his son-in-law. This can be fixed by him having a new child an arranging for it to be a boy.

* ComicBook/RasAlGhul has tried to offer heirship to his criminal empire to both ComicBook/{{Batman}} and ComicBook/{{Bane}} by way of a marriage to his daughter Talia. It didn't work out in either case.