A state has another under their umbrella as a vassal state. The vassal state is expected to be loyal, pay tribute and committed to their host state's call. However, that vassal state is still its own country and its ruler could get uppity and even help an adversary. How can the host country maintain control? Have a hostage. In this case, a political hostage.
The political hostage is someone who is important to those in charge of the vassal state. Quite often, they end up being family members, children, heirs or someone else of importance. However, unlike most hostage situations, which are often unpleasant, political hostages are usually treated quite well, given comfortable lives and even mingling with the court. However, if the vassal state steps out of line or the hostage breaks a rule, the latter can expect harsh reprisals.
Another situation is an exchange of hostages. When two sides decide to ally with one another but don't really trust one another, they will exchange people they care about so if either betrays the other, the hostage will face the consequences. So will the other.
An empire good or bad, will often use this opportunity to educate the heir to the throne of a smaller nation to be more versed in Imperial customs and culture than their own, which helps assimilate captured kingdoms into a larger Imperial culture.
The political hostage is, to put it mildly, an insurance policy. However, sometimes the person meant to be kept in line just doesn't care and will act out as they see fit.
Truth in Television, as this was very common throughout history.
See also Hostage Situation. This is a sister trope to Altar Diplomacy, and they may actually overlap in particularly unpleasant circumstances.
- In Code Geass, Charles Vi Britannia punishes his children Lelouch and Nunnally for perceived weakness (poor Nunnally becoming a blind paraplegic as collateral damage of the assassination of her mother) and defiance (Lelouch getting angry at Charles for not trying to investigate who did it) and sends them off to Japan to be used as political hostages shortly before Britannia invaded the country. It says a lot about Charles and the Britannian royal court as a whole that the time Lelouch and Nunnally were political hostages was one of the few times in their childhoods when they were truly happy.
- Fullmetal Alchemist: When Ed, Al and Mustang refuse to comply with Father's plans for Amestris, Führer Bradley points out he could easily have Winry and all of Mustang's men killed instead, preventing them from defying the military. As a further precaution, Bradley reassigns all of the colonel's subordinates and, knowing Hawkeye is his closest and most capable ally, has her made Bradley's personal assistant.
- The Eagles of Rome: Arminius is a German chieftain's son (real name Ermanamer) sent to Rome after a Roman victory as a hostage and raised alongside a Roman general's son. They become Bash Brothers after a rocky start, but eventually find themselves on opposite sides as the hostage-taking completely backfired: instead of a German raised on Roman ideals, the Romans now have to deal with a German chieftain who knows their ways and tactics.
- This was supposed to be the idea in the New Gods story. The exchange of Scott Free and Orion, the sons of the High Father and Darkseid, respectively, each sent to the other's world to keep a truce between the two factions.
- The Mountain and the Wolf:
- The Wolf reveals that he had Missandei hostage all this time, and threatens to have her raped to death if Grey Worm doesn't comply with his demands. Fortunately, those demands amount to Grey Worm staying in Westeros to fight the Wolf instead of sailing for Naath, which he is all too happy to do.
- He also holds Varys, Qyburn, Jaime and Cersei prisoner, although he's yet to make this known to the rest of the Westeros cast.
- Inter Nos has this as a plot point. The children of nobles who willingly surrender are taken hostage, sent to the Himean capital, taught in Himean schools, and then, assuming their parents honored the terms of surrender and did not engage in rebellion against the Himean rulers, returned to their homeland, now integrated into Himean modes of thinking and acting, and thus making them more likely to support continued Himean rule, rather than suborn a revolution.
- Dracula Untold: Vlad's time as a royal hostage in the Ottoman Empire was mentioned. This was Truth in Television.
- Gleams of Aeterna: This trope is institutionalized in the Kingdom of Talig via the Laic School, where young scions of noble families train to be squires. In addition to starting young nobles on a military career track, the School also ensures old nobility's loyalty to the crown by keeping their heirs within striking range of the capital in case their parents try to rebel.
- Horizon in the Middle of Nowhere: When P.A.ODA and M.H.R.R. take over the Testament Union, putting them in charge of the worldwide history recreation, they force the Date clan into compliance by having Date Kojirou, chancellor Date Masamune's brother, also inherit the name of Hashiba Hidetsugu, Toyotomi Hideyoshi's nephew. The historical Hashiba Hidetsugu was forced to commit seppuku after a falling out with Toyotomi, so P.A.ODA keeps the Date clan in line by threatening to reenact Hashiba's falling out and make Kojirou commit seppuku if the Date clan isn't co-operative. This also puts the Mogami clan in a similar situation, as Mogami Yoshiaki's daughter Komahime was married to Hashiba and died with him.
- Judge Dee: After the judge narrowly prevents a border invasion by three Tartar tribes under prince Ooljin, it's mentioned the local khan's son will lead a diplomatic mission to make formal apologies (said local khan having secretly pledged his support of the invasion until a Chinese victory elsewhere made him reconsider).
"The Khan's son," the judge continued, "has been invited to prolong his stay in the capital as an honoured guest of the Imperial Government."The spectators started cheering. They knew that with his eldest son kept as hostage in the capital, the Khan would abide by his promises.
- In Ranger's Apprentice, The Royal Ranger books 4 and 5, the rebellious Gallican Baron Lassigny has taken the son of the Gallican King Felipe hostage in his keep. The official stance the Baron has is that the king's son had only gotten lost on a hunting expedition and has stopped in the Baron's territory for a temporary rest, but the prince is clearly a prisoner, kept locked in a tower. Baron Lassigny has aspirations of overthrowing the king, who already barely holds the throne. The cover story exists to make King Felipe look bad were he to break his son out, which would upset his fragile hold on the kingdom. Rangers Will and Maddie are sent to rescue the captured prince.
- RCN: It's a standard practice of the so-called Alliance of Free Stars to take family members of the rulers of conquered planets as hostages to ensure future good behavior. In one book, Adele Mundy intentionally blows up a ship carrying said hostages to get the rest of a convoy to surrender, knowing that their Secret Police minders would have thrown them out the airlock before surrendering anyway.
- Rivers of London: This is the solution Peter proposes to end the conflict between Father Thames (god of the upper Thames) and Mama Thames (goddess of lower Thames) - a daugher of Mama Thames goes to live upriver and a son of Father Thames goes to live in London. As Peter himself readily admits, he got the idea from Dungeons & Dragons.
- A Song of Ice and Fire:
- Theon Greyjoy begins the series as the ward/hostage of the Starks, who is treated well by them and even came to see the Starks' children as his adoptive siblings. He was given to them after his family led the Iron Islands' failed rebellion against King Robert Baratheon, who forced his father to give Theon up as a hostage to ensure the Greyjoys would not attempt another rebellion.
- After the events of the first book, the ruling-in-all-but-name House Lannister keeps Sansa Stark as a ward of the court even after her engagement to their son Joffrey falls through as political leverage over her older brother Robb, who is rebelling against the crown.
- In the backstory, Aerys Targaryen kept his daughter-in-law Elia Martell and her children as hostages in King's Landing instead of sending them to Dragonstone with Rhaella and Viserys, to ensure Dorne remained loyal to him throughout Robert's Rebellion. House Martell actually considered this insulting as they would always support whatever side Elia was on, although Aerys was well-known for being paranoid. This backfired horribly, as it meant Elia and children were stuck in the Red Keep during the Sack of King's Landing and ended up being murdered by enemy forces.
- Barbarians has Arminius grow up in Rome as a hostage for his tribe's loyalty to Rome. However, this is mostly Artistic License – History as the historical Armininius Majored in Western Hypocrisy and was sent to Rome by his father voluntarily rather than Rome requesting him as a hostage.
- The Expanse: In season 5, the terrorist Marco Inaros declares war on Earth and sets out to unite the entire Outer Planet Alliance under his Free Navy banner. As part of a deal with Drummer's fleet, he exchanges officers as a token of "friendship" between crews. Of course, it's really just to have a spy on Drummer's ship and a convenient hostage (who is also one of Drummer's lovers) should she decide to betray him. She turns on the Free Navy to save the Rocinante and her crew, forfeiting her officer's life in the process.
- Novoland: Eagle Flag: Asule, crown prince of Qingyang, is sent as a hostage to Xiatang. He lives in the royal court and is ordered to marry Yu Ran, a princess of Xiatang.
- Shaka Zulu: While much of the series covers the rise of King Shaka, the Framing Device follows Lieutenant Farewell and his expedition's efforts to establish trade with the Zulu nation. Shaka eventually allows Farewell to return to Capetown with his emissaries, but keeps most of his crew captive so he doesn't get any funny ideas. Farewell later returns to free his crew, which Shaka allows. Having already come to terms with the fact that the "white men" tricked him and wanting nothing to do with them anymore, he could have easily just executed them all.
- Norse mythology: the battle between the &A Elig;sir and Vanir gods lasted for eternities until both sides got tired of it and made peace. This included the mutual exchange of hostages/guests. As a result, the Vanir sea-god Njördr and his children Freyr and Freya came to live in Asgard in exchange for the &A Elig;sir god Hœnir who the Vanir wanted as he was well suited to be their chieftain. In addition, the wise ancestor-god Mimir goes to live in Vanaheim as a council and in turn the Vanir send Kvasir, "the wisest amongst their men" to live in Asgard.
- Advanced Dungeons & Dragons 1st Edition supplement Kara-Tur boxed set. In the nation of Wa, the shogun's policy of "sankin kotai" requires the wives and children of daimyos (provincial rulers) to stay in the capital city of Uwaji at all times. If a daimyo does anything against the shogun's will, their wife and children will pay the price.
- Crusader Kings II: It is impossible to declare war on a ruler who holds a close relative prisoner, and the game warns you that if one of your relatives is being "educated" by another ruler, they may be killed if you declare war.
- This is a potential way to resolve one of the situations in Dragon Age: Origins – Awakening. There comes a point at which the Warden-Commander, who also holds the title of Arl/Arlessa of Amaranthine, has to pass judgement on a number of cases. One of these involves a plot to overthrow the Warden-Commander, and one of the judgements which can be rendered is to "invite" a dearly loved relative of each of the suspected plotters to come and stay at the Gilded Cage which is Vigil's Keep. The plotters are brought to heel because they won't dare oppose the Warden-Commander while their loved ones are this trope.
- The Force Unleashed: Leia is being held as one to keep her father in line until Starkiller rescues her.
- Fire Emblem:
- Fire Emblem Fates: Felicia and Flora, the twin daughters of Kilma, chieftain of the Ice Tribe, are kept in Nohr as essentially political hostages in order to prevent an insurrection. Felicia is oblivious towards their hostage status, whereas Flora is well aware of it.
- Fire Emblem: Three Houses: Petra, granddaughter of the king of Brighid, was given to the Adrestian Empire as a token of their new allegiance following Brigid's defeat and vassalage at the end of the Brigid and Dagda War.
- Mass Effect 2: Current Krogan culture combines this with the role of diplomat, some of the best fighters are sent to ally clans who will be killed if their hosts should the original clan break their treaty. The reason they're the best fighters is based on the hope that should it come to war they'll hold out long enough for help to arrive.
- In Girl Genius, Baron Klaus Wulfenbach keeps children from various ruling families aboard Castle Wulfenbach. Tarvek Sturmvoraus mentions being held there had its advantages:
Tarvek: Castle Wulfenbach was the place to be. The baron was collecting the future rulers of Europa. It was the center of the world.
- Star Wars Rebels: Alrich Wren became one by Saxon after Sabine left the Empire in order to ensure that Clan Wren remained loyal.
- A famous real-life example is Tokugawa Ieyasu, who, as a boy born from the Matsudaira clan, was originally sent to be a Political Hostage to secure an alliance with the Imagawa clan, but then en route was kidnapped and held hostage for three years by the Oda clan in an attempt to force his father into cancel said alliance. His father's political savviness caused him to declare that if the Oda wanted to kill Ieyasu, go ahead, then the Matsudaira-Imagawa alliance will still be cemented and will surely whoop the Oda's ass for justified revenge. Confused of what to do, the Oda clan then decided not to execute Ieyasu and treated him like a normal political hostage (with all its luxuries) where Ieyasu met Oda Nobunaga. Later on, he's transferred as a hostage for the Imagawa clan for real where he still got more luxuries and all the important studies as a feudal era daimyo to eventually lead his clan as an Imagawa vassal when he finished his hostage period, which then he used to team up with the aforementioned Nobunaga to conquer most of Japan before eventually becoming the founder of the Tokugawa shogunate
- The Tokugawa Shogunate's Sankin-kōtai system is better known for requiring daimyos, i.e. feudal lords, to stay in Edo for half of every year. A lesser-known requirement is the (official) wives and heirs of the daimyos are required to stay in Edo throughout the year as the Shogunate's hostage.
- As late as 1748, the Treaty of Aix-la-Chapelle ending the War of the Austrian Succession saw two British peers (Henry Bowes Howard, 11th Earl of Suffolk, and Charles, 9th Baron Cathcart) act as guarentors of Cap Breton (today part of Nova Scotia) being returned to France.
- Vlad the Impaler and his brother Radu were held as hostages by the Ottoman Sultan during their childhood to guarantee the co-operation of their father
- Irish High King Niall of the Nine Hostages got his epithet by taking nine petty kings hostage.
- It was a common practice, by Chinese emperors, to welcome as hostage the sons of tributary polities and educate them to become nearer from Chinese culture and act as sureties for the good conduct of their fathers.
- The Roman Republic and rather the Roman Empire used the same method for the same purposes.
- The future Henry II of France and his brother was held prisoner in Spain as surety for his father Francis I paying war reparations.
- Gedhun Choekyi Gyima, the 11th Panchen Lama of Tibet, has been missing since May 18th, 1995. As the Panchen Lama's duties include determining who will be the next Dalai Lama, the spiritual leader of Tibet, it is widely believed that the People's Republic of China, which claims ownership of Tibet, is holding the Panchen Lama hostage in order to discourage Tibetans from rising up against the PRC.
- Three Kingdoms – Shu, Wei, Wu:
- When Cao Cao received Emperor Xian into his territory, his nominal overlord Yuan Shao "suggested" he send his family north to Yuan's territory for their safety, as Cao was beset by several enemies and on a couple of occasions his family were genuinely endangered by surprise enemy attacks. Cao recognised this as an attempt to control him, however, and made excuses why he couldn't comply until he was strong enough to oppose Yuan directly.
- Ma Teng, one of the Liang warlords, became this. Accompanied by his family, he was received by the Imperial Court and granted a title. However, when Cao Cao decided to march on the independent warlord Zhang Lu in Hanzhong, Ma Teng's son Ma Chao feared Cao Cao was actually coming to attack Liang and so launched a revolt. Ma Teng and his entire family were executed as a result. Ma Chao's reputation never recovered, with at least one political marriage scrapped because someone pointed out that Ma launched his rebellion despite knowing his father and family members were hostages, showing he cared nothing for their fate.
- The sad fate of Gongsun Huang. His father Gongsun Kang ruled the region of Liaodong as a semi-independent warlord who nevertheless paid tribute to the Imperial Court. When Kang died, his younger brother Gong took power as Kang's sons were too young. When Gong pledged allegiance to Cao Wei, note , Huang was sent to the Wei court as a hostage. When Kang's other son Yuan took over, Huang warned the Wei court that his brother couldn't be trusted. When Yuan made overtures to the rival state of Wu, the Wei court sent a punitive expedition that was repelled. Despite his warning and being well-liked in court, Emperor Cao Rui reluctantly had Gongsun Huang executed.
- Ghias ad-Din, a prince from the Sultanate of Rum (now part of Turkey), was held hostage in the Georgiannote court. While he was there King Rusudan decided to marry him and he became king consort of Georgia. A very icky marriage for several reasons, not least the fact he was her prisoner and also twelve years younger than her. (Most historians think they were married when Ghias ad-Din was seventeen and Rusudan was twenty-nine, but their daughter's birthdate raises questions. It's believed she was born in 1220 and there appears to have been no doubt about her legitimacy, suggesting Ghias ad-Din may have fathered her when he was fourteen.) Unsurprisingly the marriage was a disaster.