A series of historical murder mystery novels by Alan Gordon, set at the time that the TheHighMiddleAges was starting to tail off, detailing the adventures of Theophilos, a jester belonging to the titular Guild, an organisation that is basically YouMeddlingKids taken to Machiavellian extremes.
The Guild's self-imposed remit (executed either via subtle manipulation or just bumping the right people off at the right time) is to prevent wars, or failing that, to end them as quickly as possible, all while keeping the whole thing secret and trying not to piss off a CorruptChurch that seems to be losing its patience with them.
One of the series' more beguiling ideas is that Theophilos was Feste, the Clown from Shakespeare's ''Twelfth Night''. He's also hinted to be the Fool in ''King Lear''. The first book in the series is a sequel to ''Twelfth Night'', which sees Theophilos going back to Illyria incognito to solve the murder of the Duke.
There are eight novels in total, though hopefully more will be forthcoming without readers having to resort to standing on the author's lawn with a box of cakes in one hand and a pitchfork in the other.
!!The series contains examples of:
* AffectionateNickname: Theophilos and Claudia occasionally refer to each other as [[spoiler: 'Duchess']] and 'Fool', though the extent to which either of them is a nickname could be debated, seeing as they're just plain descriptors as well. As far as Claudia is concerned, 'Apprentice' is most definitely ''not'' this. Claudia also mentions that she always thinks of Theo as 'Feste', sometimes when he's pissed her off, but mostly involving the fun variety of SayMyName situation.
* TheAlcoholic: Theo insists he isn't one. Everyone else seems to think otherwise. Though to be fair, the booze back then was a hell of a lot safer to drink that the water. Maybe he's just really thirsty?
* CodeName: Taken UpToEleven. Jesters have a Guild Name, a purely internal name which will never be used in the field. It's mainly used to identify them to other Guild members and for administrative purposes. In addition, they adopt secondary, professional codenames while engaged in fieldwork. And then there's the names they adopt for going undercover as non-Jesters. Theophilos alone has been known throughout the series as Feste, Octavius, Droignion, and Tan Pierre, but he says at one point he's had so many code names over the years, even ''he's'' forgotten some of them.
* ClownSchool: The titular Guild. It's a front for Secret Agents to train.
* CrowningMomentofHeartwarming: So what if Helga's nearly thirteen; for the very first time in her life, she has a doll of her own.
* DeadpanSnarker: All fools are this, by necessity if not inclination. Pretty much TruthInTelevision. Alan Gordon himself is revealled to be one in the appendix of ''The Lark's Lament'', if the titles of an increasingly vitriolic exchange of essays with another historian are anything to go by.
* DrinkingOnDuty: Terence in ''An Antic Disposition'', after [[spoiler: the death of his beloved]]. He's stated to be so mashed that juggling as little as three clubs takes more effort than would need to be expended by the youngest of Guild trainees, and Terence is a full-fledged and long-serving Jester.
* DrowningMySorrows: Theophilos a few times, notably after witnessing the massacre of captives at Acre in ''The Widow of Jerusalem'' (doubles as INeedAFreakingDrink). Possibly spent the fifteen years between ''Twelfth Night'' and ''Thirteenth Night'' [[spoiler: doing the romantic version of this]].
* FiveManBand: The Fools in Byzantium are this.
** TheHero: Theophilos/Feste.
** TheLancer: Claudia/Aglaia.
** TheSmartGuy: Rico.
** TheBigGuy: Plossus 'the Colossus'. Okay, it's because he's a stiltwalker, but still...
** TheSixthRanger: Xintziphitzes.
* GoodParents: Theo and Claudia are most definitely this. To baby Portia, and their apparently HappilyAdopted Apprentice Helga, anyway. Claudia [[spoiler: basically ran out on Mark and Cecile, the kids she had with Orsino. Justified in that, with Olivia as regent, Claudia wouldn't have a say in their upbringing until Mark is old enough to call the shots]].
* HistoricalDomainCharacter: A young man called Francesco de Bernadone shows up in the first book, seems to have a way with Theo's grumpy horse Zeus, and asks Theo to come back to Assisi for a chat some day. It's pretty clear that he will, in time, become St Francis of Assisi.
* TheJester: Indeed.
* JesusWasWayCool: Most Fools, and Theo especially, have ''no'' time for the church and the clergy. But they seem to genuinely love and revere Jesus, who they refer to as 'The First Fool'. If you want to stay on his good side, do ''not'' make fun of Jesus in front of Theo.
* KarmicTrickster: The entire Guild in general and Theophilus in specific.
* KnifeNut: Theophilos. In ''The Lark's Lament'', what was supposed to be a routine visit to convince an abbey-dwelling ex-Guildmember to assume the bishopric of Toulouse has suddenly turned into an incredibly complex murder investigation, but Theo's more pissed off at having to leave his favourite knife back at the abbey. [[spoiler: It's okay, though; Claudia gets him a new one for Christmas]].
* LiteraryAgentHypothesis: The first half of the series was apparently based on papers discovered in an abbey in Ireland; the second half is based on more papers uncovered after an earthquake in an Italian village. Also implied to be the case ''for some of Shakespeare's plays''.
* MagnificentBastard: Par for the course for a successful Guild operative, but Theo is this [[IncrediblyLamePun with bells on]].
* MythologyGag: In ''Thirteenth Night'', Theo is trying to work out which of Orsino's townsfolk could be the returned and revenge-seeking Malvolio. Still, at least Theo's disguised as a German spice merchant, so if Malvolio ''is'' in town, he has no idea that 'Feste' is there to look for him. When Theo arrives back at his room at The Elephant, he finds [[Theatre/TwelfthNight a pair of yellow cross-gartered stockings]] on the bed. He checks out ''immediately''.
** Similarly, Theo and Claudia's child, [[Theatre/TheMerchantOfVenice Portia]] is born on [[Theatre/TwelfthNight the sixth of January]].
* OnlyKnownByTheirNickname: Happens to Terrence, in ''An Antic Disposition''. After introducing himself as "Terrence of York" to the infant Amleth, the kid latches on to the wrong end of the sentence and refuses to call Terrence anything but "Yorick". Eventually, ''everyone'' ends up calling him Yorick.
* PlayingDrunk: One of Theo's specialities, used to eavesdrop, misdirect, or to illict InVinoVeritas from the person he's pulling it on.
* PlotHole: At the end of ''An Antic Disposition'', Claudia speculates that Theophilos is [[spoiler: Amleth]]. He isn't, he's [[spoiler: Lother]]. And considering he says in ''Jester Leaps In'' that he had to tell Claudia his real name when they got married, she should really know that...
** FridgeBrilliance: Except that he pointed out that whenever current Guild members show up in Father Gerald's stories, he always changes the names. (That could also explain why the names in An Antic Disposition don't quite match the ones from the play -- Father Gerald may have altered them.) His real name might be [[spoiler: Laertes]], but we can assume that is ''isn't'' [[spoiler: Lother]], because if it were, Father Gerald wouldn't have called him that.
* RetiredBadass: Father Gerald. Retired from fieldwork, anyway. He's still pulling the strings of a spy network that spans Europe and parts of the Holy Land despite being in his seventies and stone blind.
* SingleWomanSeeksGoodMan: More [[spoiler: 'recently-widowed' than outright 'single']], but this is the main reason Claudia married Theophilos.
* ShoutOutToShakespeare: Reasonably safe to assume that there will be many.
* ShownTheirWork: Alan Gordon is a Grand Master of this. His descriptions of life in 13th century Europe, especially Byzantium, are staggeringly detailed and evocative. Ungodly impressive when you find out he's not a professional historian. Guy's a lawyer, and is heavily involved with the Legal Aid Society. Speculation abounds as to whether he sleeps, ever. Also came up with a damn fine hypothesis as to how the life stories of Theophilos the Jester could have found their way into the hands of one William Shakespeare. If he comes across even a fleeting mention of specific jesters in any of the sources of the setting and time period he's currently working on, you can damn well expect characters either named after them or representing them to make an appearance. The sheer amount of [[HistoricalDomainCharacter Historical Domain Characters]] in general must number in the hundreds; One book, ''The Widow of Jerusalem'', seems to contain something like half the characters of ''Film/KingdomOfHeaven'' (albeit slightly more historically accurate versions). And that's before he starts adding ''Shakespeare's'' characters...
* StockUnsolvedMysteries: A rather obscure one is apparently 'solved' by Theophilos' account of the Fourth Crusade's siege of Byzantium, concerning a Venetian banner of St. Mark that was unaccountably, yet briefly, raised on one of the city's towers. This series is like porn for Medieval historians.
* TakeThat: Possibly a very, very minor one against Shakespeare, in the case of Sebastian and Olivia. Yeah, turns out marrying someone on the basis that they actually fell in love with your transvestite sister doesn't make for a stable marriage. Alan Gordon swaps these with his academic rival in the ''Lark's Lament'' appendix essay-duel.
* TearJerker: An extremely poignant one comes literally out of nowhere in ''The Lark's Lament''. The Fool Family passes a herb seller, and Theo remarks quietly to Claudia that whenever he smells herbs, he imagines being a small boy being held by his mother. [[spoiler: He never was. She was murdered immediately after giving birth to him]].
* UglyGuyHotWife: Okay, so Theophilos is by no means ''ugly'', but he's usually described as being a bit on the tall and gangly side. I think he mentions having a slightly larger than average nose at some point. Claudia on the other hand is attractive, a kickass fighter, a crack shot with a bow, something of a Fool Prodigy and was [[spoiler: willing to give up ''being a Duchess'']] to marry Theo. Helga the Apprentice muses on the fact that the female novices don't understand exactly what Claudia sees in Theo, but concludes that since Claudia loves him, and he has the complete trust of [[RetiredBadass Father Gerald]], the guy ''really'' must be something special.
* VeryLooselyBasedOnATrueStory: Quite a few of Shakespeare's plays are this, if the LiteraryAgentHypothesis is to be believed.
* WhatHappenedToTheMouse: Happens in-universe, in ''Thirteenth Night''; apparently, Viola's always found an alleged shipwreck that leaves no actual wreckage, ''and'' the survivors' luggage miraculously intact, to be more than a little bit suspect.
* WholeEpisodeFlashback: After tantalising hints in the first three books, two of these turn up at once. Book four, ''The Widow of Jerusalem'', details one of Theo's past assignments in the Holy Land, and book five, ''An Antic Disposition'', is kind of his OriginsEpisode.
* WholesomeCrossdresser: Claudia was one for years, and is one for most of the first and second books. Though in ''Thirteenth Night'', she seems to hint that [[spoiler: Orsino got a bit of a kick out of his wife dressing up like a man. Again]].
* YeOldeButcheredeEnglishe: The appendix to the first book says that some people will probably dismiss it for not being written in this, despite the original manuscripts being written in Medieval Tuscan. TranslationConvention is firmly stated to be in play.